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Points Roundtable, Part 2: Isaac Campos on Alex Berenson’s “Tell Your Children”

Updated: Aug 29, 2023

Editor’s Note: Today we bring you the second of four installments of our roundtable on Alex Berenson’s new book Tell Your Children: The Truth About Marijuana, Mental Illness, and ViolenceThis post comes from Isaac Campos, history professor at the University of Cincinnati and good friend of Points. He discusses Berenson’s use of his research, as well as issues Campos has with Berenson’s larger argument.

First, we’ll run an interview with Campos, followed by an unpublished working paper that Campos first presented at the Cannabis: Global Histories conference in Scotland last April. This paper, titled “Leopoldo Salazar Viniegra and Marijuana’s Great Historical Disjuncture,” elucidates on the ideas that Berenson used in Tell Your Children, but gives much greater historical context for Campos’s claims. 

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Isaac Campos: I had no idea. I’d never heard of him until a journalist wrote to me asking about his treatment of my research.

What was your reaction to the book?

I find it kind of depressing, actually. And I’m not talking about his argument. It’s the approach and the response that I find depressing. He looks at an exceedingly complex issue, finds a lot of conflicting evidence, only uses the evidence that supports his thesis, then writes a really sensationalistic account that get lots of attention in a media landscape that rewards sensationalism and shock value. A lot of very serious and ethical scholars have been carefully studying these questions for many years. There are significant disagreements about what’s going on, but serious scholars are looking at this stuff carefully and meticulously, all the while keeping in mind that real people are affected by what we publish, so we need to respect the data.  

And then you get this former journalist and fiction writer who comes in, writes a sensationalistic book without a single footnote, but he says that the research is at this point clear, that “everything you’re about to read is true,” and characterizes those who don’t agree with him as the “cannabis lobby.” And he’s rewarded with a bunch of media coverage and book sales. So, yeah, I find it a little depressing. It’s also frustrating because I do think it’s important to take the potential risks of cannabis very seriously, as the paper we’re posting here demonstrates. But those risks need to be assessed within the whole complex of issues related to drugs, drug policy, and harm. Historically, a lot more harm has been done by bad drug policy and the propaganda used to justify it than by the drugs themselves. This book is closer to propaganda than a useful contribution to the discourse.

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He completely ignored my actual argument. He just cherry-picked the bits that were useful to him. So he notes that everybody in Mexico presumed that marijuana caused madness and violence, that there were lots of reports that it did, and that Mexico prohibited marijuana on its own seventeen years prior to similar legislation in the U.S. Ok, yes, that’s all there in the book. But he also writes that Mexicans “had no cultural reason to view marijuana negatively.” That’s kind of a giant red flag that he either didn’t read the book, or that he’s only willing to see evidence that supports his point of view. Basically my whole book is dedicated to demonstrating the multiple and very deep historical/cultural reasons that marijuana came to be so widely associated with madness and violence in Mexico.

Here’s the very condensed version: The experience with very strong hallucinogens created a cultural atmosphere where it was considered normal that supposedly “indigenous” Mexican drugs could cause extremely powerful psychotomimetic effects. Cannabis is not indigenous, but by the nineteenth century it was widely thought to be. That cultural atmosphere made it very easy to believe that marijuana also produced powerful psychotomimetic effects, even though its effects were extremely mild in comparison to those of, say, peyote or psilocybin. And a slew of other factors helped to nurture this idea: the traditional association, first made by the Church, between indigenous drugs and the devil; marijuana’s despised user populations (mostly prisoners and soldiers); the widely accepted association between drugs, especially alcohol, and violence; the association between cannabis and much-feared indigenous healers; and the intellectual dominance of nineteenth century degeneration theory. None of this makes it into Berenson’s book, of course, nor does my actual conclusion about the cannabis-madness-violence question, which I state quite explicitly:

“Marijuana, a psychotomimetic substance well known to produce paranoid reactions in users, would have been a very dangerous drug under these [cultural] circumstances, especially in the often highly stressful environments of prisons and soldiers’ barracks… We therefore might  also presume that marijuana use ‘caused’ violence in such scenarios, though only because its use occurred in this very specific cultural setting. (emphasis added for this interview)

“This appears to be the most plausible explanation for the hundreds of reports that marijuana produced ‘mad’ behavior and violence in Mexico a century ago. There were simply too many reports, from too many different sources, with virtually no counterdiscourse, to believe they were all fabricated. At the same time, exaggeration and sensationalism were clearly also part of the equation, fueled by prejudice and fear of the highly marginal people who smoked (or sold) marijuana. Ultimately, reality and myth surely fueled each other. Sensationalism and expediency (that is, the insanity defense) likely reinforced beliefs that themselves fueled stereotyped responses to marijuana’s pharmacological properties, thus fueling more sensationalism.” (180)

I mean, you don’t even have to read the whole book to find that. You just have to skip to the chapter titled, “Did Marijuana Really cause ‘Madness’?” Now, obviously, not everyone is going to agree with my arguments, and I admit that they don’t fit easily into a tweet. But if you’re going to use the evidence, especially if you know nothing about the historical context, you should perhaps at least mention that the guy who found and analyzed all of this evidence doesn’t agree with your simplistic, black-and-white interpretation.  

Furthermore, my overarching argument is that the way we talk about drugs and characterize drugs really shapes the way people behave when they take those drugs. I’m hardly the first person to make this argument, as I’m very clear about in the book. It goes back many decades. It’s also been written about in popular sources. Malcolm Gladwell recently wrote a surprisingly credulous summary of Berenson’s book in the New Yorker, given the fact that he had previously written a piece in the same magazine about the complexity of drug-use outcomes. Back in 2010, Gladwell elegantly explained how drug effects, in this case alcohol, are dictated not only by pharmacology, but by the psychology of the users and the setting of the drug use. As Gladwell put it then: “In other words, the frat boys drinking in a bar on a Friday night don’t have to be loud and rowdy. They are responding to the signals sent by their immediate environment—by the pulsing music, by the crush of people, by the dimmed light, by the countless movies and television shows and general cultural expectations that say that young men in a bar with pulsing music on a Friday night have permission to be loud and rowdy.” (“Drinking Games: How Much People Drink May Matter Less than How They Drink It,” The New Yorker, Feb. 15 & 22, 2010)  

This is a concept that, while very well established among scholars and pretty easily recognized by the general public (alcohol obviously has very different behavioral effects on different people), remains difficult to make stick for whatever reason (probably a deep sense that intoxication is somehow immoral). People just cannot stop presuming that some drugs are “bad” and some are “good,” that some drugs “make you mellow,” and some drugs “make you violent,” etc. The fact is that it is really hard to sort out why people behave the way they do when they take drugs.

For example, both Berenson and I write about the tragic case of Richard Kirk, who shot his wife to death after taking some legal cannabis in Colorado. Here’s Berenson actually recognizing all of the factors involved, yet concluding, not surprisingly, that marijuana was the indispensable ingredient: “Kirk existed at the center of a Venn diagram of three great American maladies—opiate abuse, financial stress, and easy access to firearms. But he’d lived there for years and never been violent, not until he ate a bite of Kandy Karma Orange Ginger (a marijuana edible).” He’d also never shot his wife in the head until he acquired that handgun, which he had purchased shortly before he killed her. Now we can blame the whole thing on the handgun, or we can blame the whole thing on the marijuana, or we can blame the whole thing on Kirk. After all, he’d been fighting with his wife so much that she’d confessed to a co-worker that he “scared her” (the last detail is conveniently missing from Berenson’s account). He also admitted he’d smoked marijuana in his twenties with some frequency, yet somehow he’d never killed anyone on all those occasions. It’s obviously a terribly tragic and difficult case. Just horrible. But let’s not throw out the many potential explanations and use it to argue that marijuana legalization is going to set off a wave of horrible crime. The fact is, we already have a wave of horrible crime. It’s going on right now in Mexico (and elsewhere). People are being killed in horrific ways as a result of the huge international black market that our prohibitionist drug policies have created.

Have you read Berenson’s book? How would you respond to the larger issues it charges?

I’ve now read enough of it to know that it’s not really a serious contribution to the scholarship. It’s a polemic. It refers to anyone who doesn’t buy the thesis as “the cannabis lobby.”  Actually there are scores of serious scholars around the world who are doing rigorous, peer-reviewed research, and who strongly disagree with the book’s argument and overall tone. However, with respect to the larger issues, I will say what others have already pointed out: that you cannot look at these issues in a vacuum. Any harms done by a tiny minority of drug users must be measured against the massive harms done by drug prohibition. Mexico’s drug violence has reached truly epic and horrific levels, in part fueled by profits from the illicit marijuana industry. “Decriminalization,” which is what Berenson is in favor of, does nothing to eliminate the deadly black market. Remember that alcohol “prohibition” in the U.S. was essentially a system of “decriminalization.” It’s true that deaths from cirrhosis declined sharply during those years, but by most other measures, including ballooning federal prison populations and the expansion of organized crime, alcohol “decriminalization” did more harm than good.

I agree with Berenson that drugs and big business are a bad combination. I’ve long favored some kind of solution that would legalize cannabis without allowing its commercialization, whether that be in the form of a government monopoly or something else. Something that both kills the black market and keeps big business out of it. I’m not sure how that would work, exactly, so I tend to leave the nitty gritty to today’s policy experts. Though I think a commercial system like the one in Colorado, when paired with serious regulation and public health campaigns, is far preferable to prohibition. I’m certainly not someone who thinks marijuana is “harmless,” as I think is pretty obvious from my work. But I still find Berenson’s book offensive for its total lack of context and its brazen misuse of the evidence. I think this book demonstrates that the evaluation of complex social problems also does not mix well with the profit motive.

Why do you think Berenson’s book is striking a chord, and what do you feel compelled, as a historian, to do in response?

It’s striking a chord among the general public because it’s sensationalistic, and, unfortunately, that’s what drives ratings and social-media “likes,” and press appearances, and so forth. It’s striking a chord among researchers because it has wildly mischaracterized the state of scholarly opinion on these questions. Berenson calls the 2017 National Academy of Medicine report “the most important” piece of evidence backing his argument. But Ziva Cooper, one of the lead researchers for that report, immediately denounced the way Berenson had mischaracterized the findings. It turns out Berenson had only used the parts of the report that backed his thesis and left out those parts that contradicted it. This is exactly what he did with my work.

What is this piece that you’re presenting here?

The paper examines one of the most legendary figures in Mexican drug history, Dr. Leopoldo Salazar Viniegra. I examine Salazar’s deep dive into the cannabis-psychosis-violence question in Mexico during the 1930s. I also examine some of the clinical files from that era in Mexico as they relate to the question. This is a working paper that I presented at the “Cannabis: Global Histories” conference at Strathclyde University in Scotland last spring. It’s not completely finished, as there are a few things I want to go a little deeper into, and it has not yet gone through the peer-review process, but I think it might already add something useful to the current debate.

As I’ve done before, I argue here that we must take the potential adverse responses to cannabis very seriously. While the vast majority of users take cannabis without significant incident, there are the outliers who, as a result of the dose taken, or their own psychology, or their cultural and physical environment, have very bad responses to the drug. I argue that this idea has not been taken seriously enough, mostly because of our tendency to presume that all drugs have a pharmacological essence that makes them either “good” or “bad,” when the reality is much messier than that.

Salazar Viniegra was perhaps the first person to clearly articulate this in North America, and I think he mostly had it right, though I take the potential negative consequences more seriously than he did, and I convey some concern about the compatibility of intoxicants and big business. At the end I argue that Colorado has basically stumbled into a good, honest cannabis regulatory system, one that both allows recreational use and is quite clear about the potential hazards. As I suggest in the piece, I don’t think cannabis legalization would have passed in 2012 if the ballot measure had been as honest about the potential negative reactions to cannabis as the state’s “Good to Know” campaign is now. This isn’t because the voters were hoodwinked—the research in 2012 was already very clear about the potential adverse consequences of cannabis use—but rather because Americans have a really hard time coming to grips with the messy reality that is drug use (though Americans certainly aren’t alone in that).

There are always going to be some casualties of drug use. But history has shown us that prohibition produces even more casualties both here and abroad. That is what “harm reduction” is all about. In my view, we need to reduce the overall harms of drug use and drug policy. Thus I think that where Colorado has arrived, almost accidentally, is a pretty good place.

This is an unpublished working paper. It has not yet been through the peer-review process. Serious comments, questions, and suggestions may be directed to Isaac Campos at

“Leopoldo Salazar Viniegra and Marijuana’s Great Historical Disjuncture”

We are in the midst of a revolution in cannabis culture and policy in North America. In the United States, cannabis has gained widespread acceptance, whether measured by public opinion polls, legalization successes, or the availability of “medical marijuana” in more than half of the country. In Mexico, a medical and recreational legalization process is underway.  In Canada, the drug is legal nationwide. Marijuana is big business, a designer lifestyle accessory, and a source of inspiration for Hollywood moguls. It has even been touted on the pages of the New York Times as a performance-enhancing drug, for parents.[1]

A century ago in North America, cannabis was widely reported to cause madness, violence, and crime. In Mexico it was prohibited nationally in 1920 as a drug that threatened to “degenerate the race.” Seventeen years later, national prohibition came to the United States fueled by stories of axe-wielding marijuana maniacs. This of course is hardly the only instance of a drug’s reputation radically evolving over time. But in the modern world such evolutions have more often been from miracle drug to menace, not the other way around. This disjuncture between marijuana’s early twentieth century reputation and its post-1960s one has thus been, in short, quite extraordinary.[2]

That fact has not been lost on either scholars or activists. Over the last half century the existence of this disjuncture has been highlighted repeatedly in textbooks, trade paperbacks, and policy debates, and to great effect. In fact I’d like to suggest that marijuana’s great historical disjuncture, at least in the way it has so far been framed, has proved a tremendous asset to the marijuana-reform movement. In the United States, the movie “Reefer Madness” has been emblematic of this process. In the early 1970s, the National Organization for the Reform of Marijuana Laws re-released the absurd 1936 film, with all of its marijuana violence and insanity, in order to directly confront the old stereotypes with mockery. It was a brilliant stroke. The film became a cult classic and, today, new warnings about marijuana’s potential dangers are effectively denounced by critics as “reefer madness” hysteria before they can gain much political traction.[3]

In Mexico the cognate emblem, and the subject of this essay, has been Dr. Leopoldo Salazar Viniegra. Salazar was a brilliant, iconoclastic (and now legendary) figure in Mexico. In 1938, at the height of the so-called “reefer madness” era in the U.S., Salazar scandalized his country by claiming that marijuana did not cause insanity, violence, or any other extraordinary effects, and should therefore be legally available much like tobacco. As we will see, his ideas were quite brilliant, though their full depth and significance was drowned out during his time, and in much of the subsequent accounts, both by the scandals that surrounded his work, and, I’d like to suggest, by the contemporary political utility of a more simple, unambiguous story.

Here I will demonstrate that Salazar constructed one of the most cogent and sophisticated explanations for the early twentieth century “myth of marijuana” as he called it. As we will see, his ideas were in many ways far ahead of their time. However his story also helps illustrate how marijuana’s great historical disjuncture has been misinterpreted, but to great historical effect.  As so often happens, the fable has mattered more than the facts.


August 3-5, 2018: Expoweed Mexico. The website features an animated soldier of the Mexican Revolution with a Zapata-style mustache, in green, and ammunition belts over his shoulders laden with joints rather than bullets. He’s holding a jar of medicinal cannabis in one hand, and a massive marijuana bud, like a bouquet, in the other.[4]

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Expoweed has become an annual affair in Mexico. In 2017 a basic pass for admission cost $1839 pesos (about $100 USD), though one could also opt for the “Expoweed Passport” which cost twice as much but included admission to the afterparty. Expoweed, far removed from the marginal spaces traditionally associated with marijuana in Mexico, is without a doubt a transnational, industry affair.  

Yet in the midst of the 2017 event’s nearly 35,000 square feet of glitzy bongs, rolling papers, vaporizers, hip t-shirts, hats, bumper stickers, standup comedy, traditional Indian dances, and scantily clad girls (in green, of course), there was an academic gathering of sorts. It was a tribute to Dr. Leopoldo Salazar Viniegra, the early twentieth century psychiatrist who had first challenged the marijuana stereotypes. There he was celebrated as a “visionary” and a man far ahead of his time. Indeed, none other than Luis Astorga, the dean of Mexican drug studies, was there to make the case.[5]

Salazar has become something of a legend in Mexico. During the 1930s, as a young, highly-trained and well-respected psychiatrist and public servant, he bravely attacked Mexico’s conventional wisdom on drugs with a confidence and flair that inspired comparisons to Louis Pasteur. He is probably most famous for creating a state morphine monopoly to serve the needs of opiate addicts. The plan, which closely resembled the kinds of “maintenance” policies championed by many drug-policy reformers today, went into effect in 1940 but was rescinded a few months later under pressure from the United States. The much resented U.S. intervention, combined with the disastrous results of punitive drug-war policies since then, has enhanced the significance of this episode (and Salazar’s profile) in contemporary drug-policy debates in Mexico, providing it with a particularly poignant symbolism.[6] With respect to marijuana, which constituted his second line of attack on the drugs status quo, he was never able to go beyond the research and publicity stage, though, tellingly, that alone produced at least as much domestic controversy as his plan for the state to provide opiate addicts with cheap, high-quality morphine.

As the front page of El Universal screamed on October 22, 1938: “DOCTORS OF THE ACADEMY SMOKED DOÑA JUANITA.”

“‘Poor slandered and lovely mariguana bush!,’ cried out Leopoldo Salazar Viniegra before the indisputable seriousness of the Academy [of Medicine] at the conclusion of an erudite essay—thirty four single spaced pages—in which he turned into the most sincere apologist for the fierce and smelly ‘Juanita.’”

According to the front page report by Jacobo Dalevuelta (now legendary in his own right), Salazar capped off his talk by offering what appeared to be normal cigarettes to some colleagues from the Academy, but which turned out to contain “the green soul of white dreams.” These, an informant reported, were smoked “deliciously.” The episode would eventually top Excelsior’s list of the year’s “greatest scandals and polemics.”[7]

Marijuana was, after all, the “weed of madness,” the drug that had supposedly driven the Empress Carlota mad in the 1860s, and the inspiration for countless brawls and horrific crimes since then. Just three puffs from a marijuana cigarette were supposedly “enough to make the strongest mind reel and undermine reason in the most impulsive and implacable of dementias.”[8] Salazar was either very brave or had himself gone mad to so brazenly challenge a century of entrenched discourse in Mexico. His critics were quite happy to suggest the latter. “With respect to the doctor who makes panegyrics about marihuana,” Excelsior reported, “our informant tells us that when he is asked a particular question he forgets and has to ask [about it] various times and one observes him rambling and with strange symptoms.”[9]

Salazar was well aware of the challenge. More than a decade of clinical experience had shown him how embedded marijuana’s wicked reputation was. The families who brought in their loved ones believed it. The patients believed it. The doctors believed it. Though, as Salazar insisted that night in front of the Academy of Medicine, in all of his clinical experience, there was not one case of psychosis that could be definitively blamed on marijuana.

I went back to the clinical files to check on this. Among the thousands of surviving records from the National Psychiatric Hospital, usually called simply La Castañeda, there are indeed very few that deal at all with marijuana, much less with marijuana alone.[10] Like Salazar, I was also struck by how often cases of so called “cannabis psychosis” might have been attributed to other sources. Roberto was typical of such cases. He had begun drinking alcohol at a young age. Later he joined the army where he both began abusing alcohol and smoking marijuana. Eventually he developed a host of psychotic symptoms. Despite years of drinking, some of it very heavily, the diagnosis was “exogenous toxifrenia (marihuana).”[11]

Cecilio’s was a similar case. He was a mason who drank between two and three liters of pulque a day. Both of his parents had been alcoholics. He eventually attacked a woman savagely with a metal bar. In his various interviews he was unclear about his marijuana use, sometimes admitting to having smoked it, though on other occasions denying it. Yet, in the end, he was diagnosed with “exogenous toxifrenia (alcohol and probably marihuana).”[12] Or take José M. who had suffered from gonorrhea and malaria. He drank large quantities of alcohol and smoked marijuana daily. His family members attributed his problems to the latter, though in the hospital he was caught smoking marijuana on various occasions (it was often smuggled in) and yet never showed any signs of excitement or other abnormal behavior.[13]

It was, in short, an intellectual and cultural atmosphere dominated by the belief that marijuana was a likely and typical cause of mental illness. Yet science now suggests that any one of the many life challenges typically faced by such patients might have been the cause of their mental disturbance. Childhood trauma is positively correlated with later bouts of mental illness, as are alcohol abuse and syphilis. Psychosis also can arise through genetic predisposition.[14]

Salazar would have found none of this surprising. His theories had been inspired by the enormous gap between marijuana’s reputation in Mexico and what he’d observed in all of his clinical experience. “In all of those patients who family members or non-specialist physicians considered mentally disturbed due to the use of marijuana,” he argued, “carful observation, in all cases, succeeded in identifying a well-defined ailment, and the original hypothesis could not be sustained.”[15] All of this deeply entrenched belief was, in short, a fantasy.

Yet somehow everyone believed it. This drew the attention of Jorge Segura Millán, a young medical student who was at first skeptical of Salazar’s views but ultimately decided to dedicate his thesis, directed by Salazar, to the subject. Together they would spend a year testing the controversial psychiatrist’s theories at the National Psychiatric Hospital, called La Castañeda, and the associated National Hospital for Drug Addictions.[16]

The result was a long, fascinating study that at times makes for very entertaining reading. After a brief but quite erudite history of the cannabis plant, the thesis describes a number of experiments that were performed on dogs. To conduct these, the researchers had special crates constructed with a sliding, “guillotine-style” front door, and a glass top through which the sometimes very-stoned dogs could be observed. “Dog #2,” for example, was placed in a box in which 9.5 grams of cannabis were burned. After four minutes the dog was prostrate, slobbering, had bloodshot eyes, and no longer responded when called. After fourteen minutes the researchers opened the door. The furry subject staggered out and walked in a drunken fashion from side to side, banging into a number of objects. It finally settled on playing peacefully with the laboratory rabbits, though eventually would fight with the other dogs over food.[17]

But at the heart of the study were many, sometimes ethically-dubious experiments with humans. These sought to prove that marijuana had few real effects beyond some physiological manifestations like bloodshot eyes, dry mouth, and increased heart rate. In Salazar’s view, these curious effects, while hardly violence and madness, were nonetheless the key to understanding how the marijuana myths had been sustained over so many years. He argued that these symptoms, which replicated those that normally accompanied strong emotions, made users highly susceptible to what he called “suggestion,” meaning the expectations of users, family members, and the wider culture. As I’ll describe in more detail below, this was really the most innovative and brilliant portion of his argument as it drew on, and in some ways predated, the most cutting edge psychological research into the physiological origins of emotions.[18]

It was this theory that dictated the quite controversial methods that Salazar and Segura Millán utilized in their research. These involved carefully rolling cigarettes to mimic the commercial product, but filling them half with marijuana, half with tobacco. These trick cigarettes were then given to unsuspecting subjects, from marijuana novices to the mentally ill, to gauge their reaction. Segura admitted that some considered this mode of investigation “immoral,” but, he argued, “understanding the scientific end that was sought, they would find it justified.” The goal was simply to erase the factor of suggestion, and this was, in their view, the only way to do it.[19]

Salazar was clearly less concerned about appearances. At one point he left a pack of these trick cigarettes lying around his home. A nephew of his found them and, thinking they were simply tobacco, smoked them with friends who ranged in age from 9-14. The children soon felt their hearts racing and became so nauseous and anxious that they confessed the whole thing. Today, of course, in an atmosphere of comparable societal tolerance for marijuana, this would get just about any researcher fired. But in 1938 Mexico, at a time when most people thought marijuana caused madness, Salazar reported on this accident enthusiastically before the Academy of Medicine because, he emphasized, it proved beyond a doubt that the marijuana in the cigarettes was very active![20]

However, as Salazar would also emphasize in his presentation to the Academy, and as Segura’s longer thesis demonstrates, many of the unsuspecting subjects didn’t even notice they were smoking cannabis. If they complained of anything, they usually mentioned a rapid heart rate and dry mouth.  To demonstrate this, Salazar highlighted the experience he and his colleague, Dr. Francisco Elizarrás, had at a meeting of the Mexican Neurological and Psychiatric Society. In the midst of that august gathering, they graciously offered the trick cigarettes to the doctors sitting near them, proving, “that the marijuana was without a doubt effective.”

“For soon there appeared a reddening of the conjunctivas and the drying of the mouth that forced our colleagues to run their tongues repeatedly over their lips. And, nonetheless, during the discussions, that were frequently lively, we couldn’t detect changes of either quantity or quality in the smokers, who proceeded in their normal manner, that is to say, with neither unaccustomed slowness or brilliance. One of them was surprised…because, quite unlike him, at the end of the session he had been overtaken by an unusually strong appetite.”[21]

Again, for Salazar, marijuana did not produce any remarkable effects, whether good or bad. As much as the knife-wielding marihuano, or marijuana addict, was a myth, so were the “artificial paradises” that supposedly inspired poets and artists to new heights. Responses beyond the normal physical symptoms were, he argued, a product of “suggestion.”

Though Salazar did not make any specific reference to the scientific literature on this, it seems likely that his work was influenced by emerging research on the physiological origins of human emotion. In the late nineteenth century, William James and Carl Lange had each proposed that emotions were essentially the psychological manifestations of specific physiological changes. Where previously it had been argued that emotion came first and the physical response second, the so-called James-Lange theory suggested that it was actually the other way around.

Initially this was understood to mean that each emotion responded to a specific and distinct physiological signal. But subsequent work seemed to show that the same physiological cues governed the whole range of emotions. Then, in 1922, a critical intervention was made in the debate, and one that seems likely to have influenced Salazar. In that year the Spanish physician Gregorio Marañon showed that physiological cues were not alone enough to trigger an emotional response. To prove this, he injected subjects with adrenaline, a substance that produces the same kinds of physical responses linked to emotions—rapid heart rate, flushed face, dry mouth, etc.—and asked them to reflect on how they felt. Most of them simply reported their physical state without an emotional component, though when the patients were given a cognitive cue, their symptoms were transformed into emotions. Later, in 1962, in a more controlled and now classic study, Stanley Schachter and Jerome Singer would build on Marañon’s work by demonstrating their ability to graft different emotions (either anger or euphoria) onto the physiological arousal of subjects who had received surreptitious injections of adrenaline.[22]

Salazar, perhaps also influenced by Marañon, forwarded a very similar theory with respect to marijuana. He argued that it was no accident that users of marijuana were so prone to “suggestion” given the drugs’ real physiological effects:

“Vasomotor [phenomena] translated as tachycardia, palpitations, paleness of the face, redness of the conjunctivas, paresthesia in the members consisting of a sensation of fatness. Now then, these phenomena are of a purely emotional nature; furthermore, they are emotion itself given that the latter cannot exist without the existence of the former; one can add others of the same origin even though they don’t always occur in emotional states; dizziness and a vertiginous sensation and others that, though not strictly of the vasomotor order, typically accompany the emotions: these are tremors and dryness of the mucous membranes, principally of the mouth and nose. These phenomena, I repeat, are real and constant in varying degrees and duration; from them is derived the anxious state that almost always overtakes the [user] of marihuana, above all when it involves non-habituated subjects who are using for the first time.

“Through suggestion,” he went on,” fear, happiness, bravery and anger are awakened.” Marijuana would thus not only consistently produce certain organic, physical reactions on the central nervous system, but also a psychological reaction driven by suggestion due to the “the great number of representations that it brings with it.”[23]

The experiments provided considerable evidence to support this argument. When marijuana-naïve subjects experienced any effects at all (some of them didn’t), they tended to be those consistent physiological manifestations. A few behaved unusually but far from the aggression or madness that Mexican lore suggested should accompany marijuana intoxication. A certain “Dr. A.V.,” for example, smoked two of the trick cigarettes in succession and about ninety minutes later experienced extreme hunger. Though he did not normally drink alcohol, he felt compelled to slip into a cantina to drink a beer and eat some sandwiches.[24] Further supporting Salazar’s theory were the reactions of some of the novices when later told the cigarette they had smoked contained marijuana. Upon hearing this, one of the doctors claimed he’d experienced unusual facility for forwarding his arguments. The wife of another professor said she’d managed to stand for a very long time waiting for her husband to get home, yet hadn’t gotten tired. But some of those who had been given pure tobacco, but told that it was marijuana, also attributed various odd symptoms to the experience, like migraines, sleepiness, and clumsiness.[25]

Other experiments involved having non-users take the drug but with their consent. These incorporated a huge diversity of subjects, including students, clerks, doctors, laborers, and the researchers themselves, but produced none of the extraordinary outcomes attributed to the drug.  “We’ve observed various phenomena, some of them real and some attributable to suggestion, but, in general, few when dealing with even-keeled and cultured people.” Most of these subjects actually found the experience disagreeable and, if they smoked a second time, it was because the researchers insisted that they do so.[26]

Finally, experiments were done on mental patients using both the trick cigarettes and some of pure marijuana. Six patients were utilized for this, chosen specifically because the nature of their ailments made them likely to have “exaggerated” reactions to the supposed effects of the drug. These included two maniacs whose “agitation” was of “medium intensity”; two paraphrenics; and two paralytics (presumably what today is called “conversion disorder”). These patients showed no change in their behavior whatsoever, and only the paraphrenic wanted to keep using it afterward, though he insisted it had no effect on him.[27]

In sum, Salazar argued that user experiences were almost wholly a product of “suggestion” fueled by the formidable reputation the drug had developed over the years whether in Mexico, the U.S., or North Africa. In Tunisia, he explained, cannabis smoking was an “archaic custom” maintained by the stories weaved by Muslim bards and books like The One Thousand and One Nights. In addition, and drawing from the work Dr. J. Bouquet, an internationally known cannabis expert, he noted that given, “the proverbial indolence of the Muslims for whom work is [considered] the most awful of illnesses, their excessive pride, greedy for pleasures that they can only enjoy in feeble proportion…for their disordered imagination it is marijuana that is best suited to stimulate their imaginative faculties.”

“These perform their ritual, meeting to smoke with the deliberate and firm aim of making themselves happy and content. And with good reason, as these are almost always miserable people to whom reality denies all pleasure and felicity! They explode in contagious gales of laughter that overcome all; imaginative debaucheries or propitious libations evoke extravagant and lustful acts; these could occur on any given vulgar and explicable occasion, but the stories disseminated by them, now considerably adulterated, are seized by the legend and, in the mouths of journalists and literary folklorists who don’t wear the chlamys of the scientific investigator because it is not their mission, it is deformed and blown out of proportion; and that is how the myth is born of the marihuano who feels like a bird and [stories of] other hallucinations and delusions; they paint paradises suited to each person’s temperament and pastimes: for the courtesan it is sexual pleasure; for the man of letters, fire; for the poet or painter, inspiration, and for the philosopher, abstract relations that previously he could not perceive; for the coward it is bravery, and for the murderer it is refuge in impunity.”

This, he explained, had the maximum effect in the U.S. due to the youth of the country and the stifling conformist way of life there. In Mexico it had an impact for the same reasons as in the Muslim world: because the poor had to look for happiness in fantasy.[28] Salazar capped off his extraordinary performance before the Academy by handing out some trick cigarettes to various colleagues.

Over the coming weeks the headlines would fan the controversy. On Oct. 24, in El Universal, Dr. Manuel Guevara Oropesa, President of the Mexican Association of Neurology and Psychiatry, published a rebuttal to Salazar Viniegra’s views, while El Nacional featured a lawyer’s claims that Salazar should be jailed for encouraging marijuana use (there was certainly some justification in the Penal Code). At the end of the month, the journal Criminalia published Salazar’s paper in full, along with an alternate viewpoint from another Mexico City physician.[29]

In November the controversy continued. On the first, the front page of Excelsior announced in bold type, “Dr. Salazar Viniegra is Accused of Giving Marijuana to the Crazies.” There followed testimony from the father of a young patient at La Castañeda who said that his son had been turned into a marijuana addict at the hospital. Soon after, the Director of the Hospital for Drug Addicts, Dr. Fernando Rosales, wrote in to complain that the information in the piece had been “inexact,” claiming that no one had been obliged to smoke marijuana, though, as we’ve seen, this was clearly false. He would reiterate this argument in a private meeting with inquisitive U.S. Consular officials while noting that he had led his own experiments on marijuana like those conducted by Salazar, and had come to similar conclusions. He also insisted that patients at the hospital were not allowed to smoke marijuana except during experiments. Later, in mid-Novermber, U.S. Vice-Consul Norman L. Christianson attended one of these experimental sessions. There, according to Christianson, Dr. Rosales and Segura admitted that they had indeed done experiments with the drug on the patients at the insane asylum. He also seems to have smoked some marijuana himself while observing a number of other inconsistencies.

“At Dr. Rosales’ direction one of the patients gave Mr. Christianson a marijuana cigarette, which was puffed a few times and given back to the patient. The patient said that after one has smoked two or three marijuana cigarettes he prefers them to any other. However, Dr. Rosales said that they had proved marijuana is less habit forming than tobacco. The three smokers appeared to be completely normal after smoking one marijuana cigarette apiece.

“When we first arrived at Dr. Rosales’ office, he asked an assistant if any of the patients had marijuana in their possession. No one admitted having it, and so Dr. Rosales sent over to another office to get a small amount. It appears that Dr. Rosales expected the patients to have marijuana although he stated to Mr. Christianson on November 4, 1938, that the treatment at the hospital consisted partly in forbidding the patients to smoke the plant. Mr. Christianson believes that Dr. Rosales and Jorge Segura Millán are so certain of the correctness of their theory about marijuana’s harmlessness that they are not concerned if some of the patients smoke it occasionally.”[30]

In Late November, a piece in El Universal seemed to openly mock Salazar’s views, leading Ambassador James Stewart to comment that, “Ridicule is no doubt the best weapon with which to combat the dangerous theories of Dr. Salazar Viniegra.”[31] U.S. officials made a translation of Salazar’s “Myth of Marijuana,” and in the section where Salazar noted that his views were based on “14 years of continuous practice in the Insane Asylum,” someone scrawled in pencil:  “Possibly 14 years incarceration.”[32]

Salazar was no doubt brilliant, but it is also fair to say that he was at times so reckless that it blunted the impact of his ideas. After the fireworks of the fall, Salazar’s theories had no discernable impact on Mexican marijuana policy, at least during his lifetime.

But was he right?

I’ve argued elsewhere that, during the nineteenth and early twentieth centuries, various factors in Mexican history combined to create a cultural setting conducive to violent responses to marijuana’s natural effects. Not, I must emphasize, because marijuana necessarily causes violence, but because the social and cultural circumstances of the drug’s use in Mexico on some occasions produced violent results. I’ve also argued, following from the more recent science on the drug, that marijuana’s links to “madness” derived from those natural effects being “psychotomimetic,” and from the still unexplained correlation between cannabis use and schizophrenia.[33] Clearly there is a kinship in our points of view, but they are also quite distinct.

In part the difference stems from our moments in time. While we both have sought to explain the overwhelming belief in Mexico that marijuana caused violence, madness, and other extraordinary effects, Salazar was writing in the very thick of those deeply entrenched discourses. If he could simply show that marijuana did not produce “VISIONS, AGGRESSION, AND HALLUCINATIONS” as Segura’s thesis repeatedly emphasized in capital letters, then he had won the argument. Countering the widespread belief in these extreme outcomes was the goal. My work has been written in a diametrically opposed atmosphere. Today, at least in popular discourse, such claims are often waved off as simply “reefer madness” hysteria. Though I think Salazar’s work helps to illustrate that neither is it quite that simple.

Consider that Salazar and Segura reported a number of their subjects having quite adverse reactions to cannabis. We’ve already seen how Salazar’s nephew and friends became panicked and nauseous from the trick cigarettes. But there were a number of other subjects who experienced similar adverse reactions from both swallowed and smoked cannabis. “J.I.A.,” for example, who was described as a “pure marijuana addict” experienced a few moments of anxiety with fear after taking four grams of the fluid extract. “S.P.,” an employee of the psychiatric hospital, and not an addict of any kind, took half a gram of the extract and experienced nothing unusual. But with a gram he became nervous:

“Extreme thirst with extremely dry mouth, not habituated to intoxicating drinks he felt the necessity to drink something for his thirst and he went to a bar, but he had to leave without drinking the beer because he found himself extremely nervous and he had a feeling of intense fear; generalized sweating, intense congestion of the face and eyes, but without the ability to explain it, which made him think that everyone recognized in his face that he was intoxicated. He did not present hallucinations, visions, or aggressiveness; on the contrary, he says that he did not want to run into or make any friends for fear of being discovered. He notes that the streets seemed to get longer. He went to bed two hours earlier than normal, slept deeply until the next day when he woke up completely fine. He did not have any of the discomforts that alcoholic intoxication leave. He notes that he did not experience any pleasure, rather, on the contrary, he is disposed to never [use] it again.”[34]

There were other cases of this kind, but because the aim was to prove that marijuana did not produce madness or violence, they were easily written off. Segura himself smoked two of the marijuana cigarettes as was recommended to him by seasoned users, and had an intense anxiety reaction accompanied by significant fear. Another medical student, after smoking a similar amount, also became very frightened. A female subject responded in a similar way. Another very experienced and unusually articulate user described such bad reactions in detail. “When there is a certain excess, one is overcome by a very specific mental state, one experiences a feeling of inferiority which is translated into a kind of fear mixed with shame and depressing ideas, marked by a certain mental propensity to believe in syncope or collapse, which in my case has never occurred but which I have witnessed in a neophyte.”[35]

Finally, and of particular importance, were various negative outcomes when cannabis was mixed with alcohol. One female subject was given cigarettes of marijuana mixed with tobacco after having already ingested several cocktails. She soon began vomiting and entered into “a spasmodic crisis of laughing and crying,” along with convulsions, before falling into a deep sleep. Her friend had a similar reaction of wild laughter and intense convulsions.

These were explained as being simply the symptoms of alcoholic intoxication in the first, and hysteria in the second, and thus having had nothing to do with the cannabis.[36] To prove it, various subjects were given large doses of alcohol followed by marijuana. Two subjects were asked to drink about 10 ounces of mescal over the course of an hour. While one of the subjects continued to act normally, the second, “F.L.M.,” swayed about completely drunk, and with slurred speech bragged that he was the “better drug addict” of the two. Each was then given a pure marijuana cigarette to smoke. FLM had to lie down, leading the other to comment that his friend lacked stamina. This nearly provoked a fight and the two had to be separated.

Segura explained that F.L.M. had previously been in prison and was known for acting like that when he was drinking, thus the role of marijuana was totally discounted. And, to be clear, various other subjects mixed alcohol and marijuana to no ill effect.[37] But under questioning, many of the more seasoned users, while emphasizing never having experienced “visions, hallucinations, or aggression” while using marijuana alone, argued that the combination of alcohol and marijuana indeed produced violence. E.L., a thirty-year-old heroin addict, noted that, “when marihuanos mix marijuana with alcohol they become very irritable and quarrelsome.” S.R., another heroin addict, claimed that while he’d never seen a pure marihuano be aggressive, “He’s seen alcoholics who mix that intoxication with marijuana, and who when they are completely drunk get worked up ‘like crazies.’” J.G., a thirty-nine-year-old marihuano, similarly reported that people who mixed alcohol with marijuana wind up “acting like madmen.” J.V.E., another thirty-two-year-old heroin addict, admitted that when he mixed marijuana with alcohol there followed “brutalities, fights, and seeing things differently.” Several others reported similar outcomes in themselves.[38]

Salazar considered all of this unimportant because, he argued, alcohol produced similar effects on its own.[39] But we now know that the relationship between alcohol and aggression is also culturally constructed. Alcohol does not lead to violence in all or even most contexts. Indeed, all drug use outcomes are to some degree or another dictated by culturally-determined user expectations, the circumstances of the drug’s use, and the pharmacology of the substance.[40] Today, for example, mixing alcohol with marijuana is not generally considered a cause of violence. Drug use outcomes are, in short, very much overdetermined. Proving that a drug, on its own, does not produce extreme behavioral outcomes does not actually tell us very much because it’s quite unusual for a drug to do so.

Thus we are left with many very messy histories and no simple answers. Consider, for example, Adolfo. He was born in 1894 in the thick of a rapidly modernizing Mexico City. Life would not be easy for him. He was one of seven children born to an “extremely nervous” mother. Of his six siblings, one was born dead, two others (twins) died before the age of three of yellow fever, and two others would become heroin addicts. When Adolfo was seven his father abandoned the family, leaving them in “a bad way,” (en malas circunstancias) and he and his brothers were turned over to an orphanage. Adolfo was a timid and cowardly child. He feared his father, never daring to look up at him when they spoke. His intellectual abilities had always been extremely limited and he never managed to become more than a mediocre student.

At twelve he worked as an apprentice for a tailor until he fell off a ladder, hit his head, and was dazed for a long time after. He then left that job to become an assistant for a curtain maker. Around this time, he began hanging out in second rate theatres (“tiatruchos”) and partying till the middle of the night. At fourteen he tried marijuana with very unpleasant results. As he described it to the staff at La Castañeda: “he saw a long road without end that he walked daily, he felt nervous, slamming himself against the ground, provoking quarrels with his friends and forcing them to fight.”

This was a classic manifestation of “marijuana madness” as it was known in Mexico. But marijuana was hardly Adolfo’s only problem during this period. He was living like a vagabond and was detained (enganchado), probably illegally, and sent to work on a plantation in the coastal state of Campeche where he contracted malaria and suffered from sores all over his body. There he almost starved to death while begging for the scraps necessary for survival. In 1916 he joined the army where his comrades would try and get him to drink more alcohol and smoke more marijuana. It was typical of soldiers to force marijuana on their mentally unstable comrades just to see what would happen.[41] Adolfo managed to hold them off, but at some point he contracted both gonorrhea and syphilis.  By the time he got back to living with his mother, he was exhibiting symptoms of some kind of serious mental illness. He was having trouble sleeping, suffering from buzzing in his ears, which he described as a kind of “ringing of spirits,” and hallucinating visions of huge faces and animals. His mother reported that he’d become lazy; he claimed that he’d already done plenty of labor in his life and therefore didn’t need to do more. All of this provoked his first visit to La Castañeda where he was diagnosed with “alcoholic psychosis.” A second visit in 1924 produced a diagnosis of “exogenous toxifrenia (alcohol and marihuana).” A final visit a year later involved increasingly paranoid delusions and resulted in a diagnosis of “Paranoid dementia praecox.”[42]

Adolfo had lived a difficult life involving some childhood trauma, a “nervous” mother, drinking from an early age, all night partying, a severe blow to the head, a stint in the army, malaria, syphilis, forced labor, and near starvation. More recent research suggests that any of one these factors might have played some causal role in his mental illness. Most of the cases I examined contained similarly complex backstories. In Mexico marijuana was used overwhelmingly by the country’s most marginal people for whom life was often very hard indeed. In short, a very far cry from Expoweed 2018.

Salazar was aware of this and was thus pushing back against the lurid, simplistic, and exploitative portrayals of marijuana’s effects in public discourse. He was certainly correct to do so, and in most ways he was right. He made the fascinating suggestion that marijuana, because of its peculiar physiological effects, was especially likely to produce emotional responses onto which cultural messages might be grafted. Given what we’ve learned since then about the physiological origins of emotions, this idea probably deserves more attention from researchers, though we also know that all drug use outcomes are to some degree culturally determined.

However, Salazar, who famously advocated for marijuana legalization, understood that this theory could be read in more than one way. “One could say, of course, that given that marijuana opens the door to all of these suggestive influences, its repression is justified; but this is only true in part, for it is more likely to be successfully done away with when the truth strips it of its tempting attributes and it loses its efficacy as sorcery.” In other words, by revealing the truth and stripping marijuana of its magical reputation for inciting both great harms and pleasures, the ultimate goal of eliminating its use might actually be achieved.

The 1960s then radically altered marijuana’s historical trajectory. In the United States its use was adopted by a new generation in an atmosphere in which powerful psychotomimetic drugs, principally LSD, were being touted as tools of “mind expansion” and psychic health. Pushing the boundaries of madness became a way of breaking down mental barriers and potentially revolutionizing society. At the same time, decades of demonization and association with marginal groups made marijuana highly attractive to this emerging counterculture. As Norman Mailer put it, marijuana became the “wedding ring” that connected black and white culture:

“So no wonder that in certain cities of America, in New York of course, and New Orleans, in Chicago and San Francisco and Los Angeles, in such cities as Paris and Mexico, D.F., this particular part of a generation was attracted to what the Negro had to offer. In such places as Greenwich Village, a ménage-à-trois was completed—the bohemian and the juvenile delinquent came face-to-face with the Negro, and the hipster was a fact in American life. If marijuana was the wedding ring, the child was the language of Hip for its argot gave expression to abstract states of feeling which all could share, at least all who were Hip.”[43]

There were still the occasional reports of “cannabis psychosis,” but these were overwhelmed by its very noisy countercultural adoption and celebration by a highly privileged baby-boomer generation.[44] Soon marijuana’s reputation was transformed, “from killer weed to drop-out drug,” and a new mythology was propagated suggesting that its demonization in the United States was a global anomaly.[45] Scholars and activists sought an explanation for what was now a very obvious disjuncture in marijuana’s twentieth century history, and various theories—the “Mexican hypothesis,” the “Anslinger hypothesis,” and the “hemp conspiracy”—were born, none of which even entertained the idea that there might have been any truth in the old stereotypes.[46] In the midst of all of this, the film “Reefer Madness” was re-released, and together these factors simplified marijuana’s twentieth century disjuncture into an unambiguous and, not coincidentally, politically-potent story. All of this reflects the widespread tendency in western society to see drugs as neat pharmacological vessels that produce specific results regardless of the surrounding circumstances of their use.

But, despite the resulting cultural climate, one highly conducive to positive marijuana experiences, something like “reefer madness,” though incredibly rare, nonetheless still manages to break out. Two recent cases, both in the first few months after Colorado legalized recreational marijuana, illustrate the point. In the early morning hours of March 11, 2014, a college student named Levy Thamba jumped to his death from a Denver hotel balcony after ingesting a marijuana cookie containing 65 mgs of THC, or 6.5 servings. Before taking his fatal dive, Thamba, whose speech had become erratic, had begun tearing things from the walls and acting hostile.[47]

A month later, a man named Richard Kirk ingested some portion of a “Karma Kandy Orange Ginger,” a marijuana edible about the size of a Tootsie Roll that contained 10 servings of THC. Soon he became extremely aggressive. His wife called 911. Richard had consumed marijuana, she said. He was raging. He insisted she shoot him with the gun still locked in its safe. He was hallucinating and ranting about the end of the world. He was trying to get into the children’s room.

Kirk eventually unlocked the gun safe and shot his wife in the head while she was on the phone with 911. He would later plead not guilty of murder by reason of insanity. It was madness, he said, and cannabis had produced it. His lawyers had expert witnesses ready to testify that marijuana was at least partially to blame. “It is my professional opinion,” stated Dr. Andrew A. Monte, MD, a medical toxicologist at the University of Colorado Hospital, “that Mr. Kirk was intoxicated with THC leading to delirium and psychotic-like symptoms at the time of the homicide.”[48]

In the end, Kirk pursued a plea bargain in order, he said, to spare his children from having to testify, but he continued to insist that the Karma Kandy had driven him temporarily mad. Indeed, his children have maintained that position in a lawsuit against Karma Kandy’s manufacturer. Though, as with so many cases from the past, there was also reason to suspect the cannabis was simply a useful excuse for murder. The prosecution found that Kirk and his wife were under considerable financial stress and that she had recently confessed to a friend that she was scared of her husband.[49]

Nonetheless, shortly thereafter, and given that both Thamba and Kirk had bought small edibles containing huge doses of THC, Colorado wisely passed new regulations that required such products to be packaged in no more than single-serving doses. Colorado also began its “Good to Know” cannabis safety campaign to accurately warn users of potential “bad reactions” to the drug:

“The symptoms of using too much marijuana are similar to the typical effects of using marijuana, but more severe. These symptoms may include: extreme confusion, anxiety, paranoia, panic, fast heart rate, delusions or hallucinations, increased blood pressure and severe nausea/vomiting. If someone is having trouble breathing, has pale skin, or is unresponsive, call 911.”[50]

Symptomatic of nearly half a century of claims that “reefer madness” is total nonsense, these potentially dangerous outcomes are introduced in the campaign by the playful heading, “Oops, You Had Too Much.” Arguably this approach, one of truthful nonchalance, is a wise one. Users suffering from a temporary psychotomimetic reaction to the drug are surely much better off thinking, “oops I’ve had too much,” than that they are going mad, as they would have a century ago in Mexico.[51]

For many readers this will be deeply unsettling, but mostly because we have difficulty facing up to the very messy nature of drugs. As Paracelsus noted in the sixteenth century, and as countless observers have done since then in some way or another, “In all things there is poison, and there is nothing without a poison. It depends only upon the dose whether a poison is poison or not.”[52] This should be obvious enough from the stream of warnings that accompany virtually any pharmaceutical advertisement on television. Though we need to add that, in addition to the dose, the danger of drugs depends on who is taking them and under what circumstances. Again, most of us recognize this when confronted with reality. The same dose of alcohol has very different effects at a fraternity party than at a faculty gathering. But, for some, when it comes to “recreational” drugs, substances taken for that old bugaboo “pleasure,” any risk of the “poison,” however small, is too much risk, even in the face of the massive harms done by prohibition, including the many thousands of murders and lives destroyed by the resulting illicit markets. Thus all sides have their reasons to ignore the truth: for those moved primarily by the harms of prohibition, the argument is best simplified and the outliers downplayed. For those more disturbed by the occasional bad reactions, and perhaps ignorant or insensitive to the full range of harms done by prohibition, the problem becomes about little more than the outliers.

Through it all we have arrived at a fascinating historical conjuncture in part created by the widespread misreading of marijuana’s twentieth century disjuncture. Had Colorado voters been provided a ballot initiative in 2012 that included the potential “bad reactions” as described by the Good to Know campaign, legalization surely would have failed. Given the enormous harms produced by marijuana prohibition in both the U.S. and abroad over the last century, we should probably be thankful for this oversight. But such potential effects were also clearly overlooked when manufacturers were allowed to sell single-serving sized edibles that contained ten servings of THC. Only after two terrible tragedies was reality thrust upon regulators, leading to what is a relatively enlightened, regulated system with legitimate warnings about marijuana’s potential psychotomimetic effects.

In Mexico, Salazar Viniegra is often touted as the man who, far ahead of his time, understood that marijuana was “harmless.” In truth, Salazar was the first Mexican, indeed perhaps the first man in North America, to discern the immense complexity of marijuana’s effects and their relationship to behavioral outcomes. Even if he did not have it all right, we would do well to emulate his willingness to face all of that messy complexity.


  1. “State Marijuana Laws in 2018 Map,” (accessed March 21, 2018); “Mexico’s Incoming Government Moves to Legalize Marijuana”, (accessed Jan. 16, 2019);  “Legalizing Marijuana, Canada Begins a National Experiment,” (accessed Jan. 16, 2019); Mark Wolfe, “Pot for Parents,” New York Times, Sept. 7, 2012. (accessed March 21, 2018). On Cannabis and fashion, see On marijuana’s evolving legal status in Latin America, see “Weekly Chart: Where Does Latin America Stand on Marijuana Legalization?” (accessed March 21, 2018).

  2. David F. Musto, The American Disease: Origins of Narcotic Control, 3rd ed. (New York: Oxford University Press, 1999). Joseph F. Spillane, Cocaine: From Medical Marvel to Modern Menace, 1884-1920 (Baltimore, MD: Johns Hopkins University Press, 2000). As Spillane notes, cocaine experienced a short-lived reincarnation as a “soft” drug in the 1970s, and Musto has commented on the ebbs and flows of temperance sentiment with regard to alcohol in the U.S. But the total evolution of cannabis’ reputation in the United States still strikes me as quite unusual and more like that of Early Modern tobacco which was at first violently proscribed in many locations only to later gain widespread acceptance. On Early Modern drugs see Wolfgang Schivelbusch, Tastes of Paradise: A Social History of Spices, Stimulants, and Intoxicants (New York: Random House, 1992) and David T. Courtwright, Forces of Habit:  Drugs and the Making of the Modern World (Cambridge, MA: Harvard University Press, 2001).

  3. On the history of “Reefer Madness,” see Stuart Samuels, Midnight Movies (New York: Collier Books, 1983), 92-104. On the film and phrase as a useful tool of marijuana policy reformers, see, for example, (accessed March 21, 2018); “Reefer Madness Propaganda Still Exists? ‘Weed Is Making People Lose Their Minds And Memories’” (accessed March 21, 2018); 100% of New Cannabis Addiction Reports Show Signs of Reefer Madness (accessed March 21, 2018).

  4. (Accessed March 21, 2018)

  5. (Accessed March 21, 2018)

  6. For more on the incident, see Isaac Campos, “A Diplomatic Failure: The Mexican Role in the Demise of the 1940 Reglamento Federal de Toxicomanias,” Third World Quarterly, 39, no. 2 (2018): 232-247. For examples of the incident’s continued salience in today’s drug-policy debates, see: “Conspiró EU contra doctor mexicano que abogaba por legalizar la mariguana,” (Accessed March 21, 2018). Sometimes Salazar’s opiate dispensary plan is conflated with his views on marijuana. See, for example, “Honran a Leopoldo Salazar Viniegra en la Inauguración de la ExpoWeed México 2017,” (accessed March 21, 2018).

  7. “Médicos académicos fumaron ‘Dña Juanita,’“ El Universal, Oct. 22, 1938, 1; “Escándalos y polémicas que dieron calor al mexicano 1938,” Excelsior (Magazine Dominical), Jan. 1, 1939, 1.

  8. Isaac Campos, Home Grown: Marijuana and the Origins of Mexico’s War on Drugs (Chapel Hill: The University of North Carolina Press, 2012). For the quote, see page 153.

  9. “Se acusa al Dr. Salazar Viniegra de dar mariguana a los locos de la Castañeda” Excelsior, Nov. 1, 1938.

  10. Andrés Ríos Molina and a team of researchers examined a sample of the National Mental Hospital’s population, between 1910 and 1968. They examined 20% (12,296) of the more than 61,000 total cases. 10,641 of the sampled files included a diagnosis of some kind of mental disorder. Of those, 116 were linked to marijuana in some way. By comparison, 2,055 were connected to alcohol. I worked with Ximena López Carrillo, who was a lead researcher on Ríos Molina’s project, to do my own survey the archive’s records. We looked at every person who was labled as a “drug addict” (toxicómano) between 1910 and 1940. Of those 469 cases, 69 were connected to marijuana in some way. However, only 30 were connected to marijuana by itself (the majority were linked to alcohol or other drugs as well).  And of those 30, only 22 were concluded to actually have symptoms of mental illness under examination. These numbers jibe with a 1920 study done by the doctors Adolfo Nieto and Eliseo Ramírez. They found that between 1911 and 1920, there were only eight cases in the mental hospital connected in any way to marijuana. Of these, only two were exclusively marijuana users. Among the others there were four alcoholics, one alcoholic/opium user, and on morphine abuser. See Andrés Ríos Molina and Ximena López Carrillo, “Introduction,” in Los pacientes del Manicomio la Castañeda y sus diagnósticos: Una historia de la clínica psiquiátrica en México, 1910-1968, ed. Andrés Ríos Molina (México: UNAM/Instituto de Investigaciones Históricas, 2017), 19-21; DD. Adolfo M. Nieto y Eliseo Ramírez, “Notas acerca del uso de la marihuana en el Ejército”, Sección Octava, Medicina y Cirugía Militares, Memoria del VI Congreso Médico Nacional, verificado en la ciudad de Toluca del 14 al 21 de Abril de 1920, Tomo II (México:  Imprenta Politecnica, 1921), 575.

  11. RT, Manicomio General (MG), Expedientes Clínicos (EC), Caja (C.) 161, Expediente (exp.) 9175, Archivo Histórico de la Secretaría de Salubridad y Asistencia, Mexico City [hereafter simply AHSSA].

  12. CGE, MG, EC, C. 193, Exp. 10751, AHSSA.

  13. JMS, MG, EC, C. 107, Exp. 6499, AHSSA.

  14. On trauma, mental illness, and cannabis see Ingo Shäfer and Helen L. Fischer, “Childhood Trauma and Psychosis– What Is the Evidence?,” Dialogues in Clinical Neuroscience 13, no. 3 (2011); JE Houston et al., “Cannabis Use and Psychosis: Re-Visiting the Role of Childhood Trauma,” Psychological medicine 41, no. 11 (2011); Michelle Harley et al., “Cannabis Use and Childhood Trauma Interact Additively to Increase the Risk of Psychotic Symptoms in Adolescence,” Psychological medicine 40, no. 10 (2010). For a recent article on alcohol and psychosis,  see Jonna Perälä et al., “Alcohol-Induced Psychotic Disorder and Delirium in the General Population,” The British Journal of Psychiatry 197, no. 3 (2010).On syphilis: Fabian Friedrich et al., “Manifest Psychosis in Neurosyphilis,” General hospital psychiatry 31, no. 4 (2009). On the genetics of schizophrenia: Schizophrenia Working Group of the Psychiatric Genomics Consortium, “Biological Insights from 108 Schizophrenia-Associated Genetic Loci,” Nature 511, no. 7510 (2014).

  15. Dr. Leopoldo Salazar Viniegra, “El mito de la marihuana,” Criminalia 5, no. 4 (1938): 207.

  16. Dr. Jorge Segura Millán, La marihuana: Estudio medico y social (México, D.F.: Editorial Cultura, 1939), 7.

  17. Segura Millán, La marihuana, 38-39.

  18. This part of Salazar’s work also been almost completely ignored by the scholarship, presumably because the scandals surrounding him, and his calls for marijuana legalization, have tended to overshadow everything else. Luis Astorga provided one of the first detailed accounts of Salazar’s marijuana theories and covered many of the key elements, but he missed this question of “suggestion.” See his El siglo de las drogas (México, D.F.: Espasa-Calpe, 1996), 50-53. See also Ricardo Pérez Montfort, Tolerancia y prohibición: Aproximaciones a la historia social y cultural de las drogas en México, 1840-1940 (México: Penguin Random House, 2016), 287-289. In my previous work on marijuana in Mexico prior to 1920, and as I describe later in this essay, I also argued that the cultural environment was critical to marijuana-use outcomes in Mexico, though for different reasons than those forwarded by Salazar. During that research, while I was aware of the general thrust of Salazar’s views, I only dealt with them in my conclusion because he appeared on the scene after the period covered by my book. See Campos, Home Grown, 225.

  19. Segura Millán, La marihuana, 50.

  20. Salazar Viniegra, “Mito,” 216.

  21. Ibid.

  22. Stanley Schachter and Jerome E. Singer, “Cognitive, Social, and Physiological Determinants of Emtional State,” Psychological Review 69, no. 5 (1962). On Marañon’s influence, see also Randolph R. Cornelilus, “Gregorio Marañon’s Two-Factory Theory of Emotion,” Personality and Social Psychhology Bulletin 17, no. 1 (1991): 65-69.

  23. Salazar Viniegra, “El mito,” 233-35.There is some reason to question whether Salazar was building from Marañon for he compares the effects of marijuana to atropine (218) rather than adrenaline. It seems that if he’d been inspired by Marañon’s work, he would’ve used adrenaline as the comparison.

  24. Segura Millán, “La marihuana,” 47-48.

  25. Salazar Viniegra, “El mito,” 216-17.

  26. Ibid., 217-18.

  27. Ibid. 218-19.

  28. Ibid., 235-236.

  29. Daniels to the Sec. of State, “A Prominent Mexican Physician Contradicts Dr. Viniegra’s Marihuana Theories”, October 24, 1938; Mex-LSV; BNDD; RG 170; NARA; Stewart to the Secretary of State, October 27, 1938; Mex-LSV; BNDD; RG 170; NARA. Salazar Viniegra, “Myth of Marihuana”; Oneto Barenque, “La marihuana ante la psiquiatría.”

  30. Stewart to the Secretary of State, November 18, 1938; Mex-LSV; BNDD; RG 170; NARA.

  31. Letter from James B. Stewart to the Secretary of State, “An Article Ridiculing Dr. Salazar Viniegra’s Defense of Marihuana”, October 24, 1938; Mex-LSV; BNDD; RG 170; NARA.

  32. Stewart to the Secretary of State, December 12, 1938; Mex-LSV; BNDD; RG 170; NARA.

  33. Campos, Home Grown.

  34. Segura Millán, La marihuana, 86.

  35. Ibid., 99-102, 113.

  36. Ibid., 88-89.

  37. Ibid., 89-93.

  38. Ibid., 105-111.

  39. Salazar, “El mito,” 219.

  40. Craig MacAndrew and Robert B. Edgerton, Drunken Comportment: A Social Explanation (Clinton Corners, N.Y.: Percheron Press, 2003); Richard DeGrandpre, The Cult of Pharmacology: How America Became the World’s Most Troubled Drug Culture (Durham: Duke University Press, 2006).

  41. Campos, Home Grown, 171.

  42. ATP, MG, EC., C. 118, Exp. 7006, AHSSA.

  43. “The White Negro: Superficial Reflections on the Hipster,” (Accessed March 21, 2018)

  44. On cases of “cannabis psychosis” from that era, see Campos, Home Grown, 19-24.

  45. Jerome L Himmelstein, “From Killer Weed to Drop-out Drug: The Changing Ideology of Marihuana,” Contemporary Crises 7, no. 1 (1983): 13-38. On the U.S. as exception, see Allen Ginsberg, “First Manifesto to End the Bringdown,” in The Marihuana Papers, ed. David Solomon (New York: New American Library, 1968), 238-39.

  46. On the evolution of this literature, see my forthcoming “Mexicans and the Origins of Marijuana Prohibition in the United States: A Reassessment.”





  51. Nearly fifty years ago, Andrew Weil, based in his own clinical experience, argued that when users suffering from adverse cannabis reactions were simply reassured that everything would be ok, as opposed to being told that they were experiencing “acute toxic psychosis,” they tended to recover quite swiftly. See A. T. Weil, “Adverse Reactions to Marihuana. Classification and Suggested Treatment,” New England Journal of Medicine 282, no. 18 (1970): 997-1000.

  52. Campos, Home Grown, 43.

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