Psilocybin for Treating Violent Behavior

Psilocybin as a Means of Curbing Violent Behavior 


Within the last four years, two prominent psychology researchers published reports related to the effects of hallucinogens and their potential for providing ‘protective effects’ against violent behavior. These studies garnered national attention and caused some news outlets to proclaim “LSD and Magic Mushrooms Could Beat Domestic Violence” and “Psychedelic drugs may reduce domestic violence.”  While it is understandable that any such research into psychedelic drugs is liable to stir excitement (particularly in regards to the long moratorium on psilocybin research), what are these latest articles really telling us? Do the new studies really examine psilocybin specifically? And how strong are their findings? This overview examines the methods used in these studies in order to understand their limitations and how they might be considered a springboard for future research.

Psilocybin’S Stigma

The stigma surrounding hallucinogens – particularly psilocybin (the naturally-occurring compound found in “magic mushrooms”) is well- known. During the societal paradigm shift of the early 1960’s, Harvard Psychologist Timothy Leary advocated hallucinogens as a way to ‘turn on, tune in, and drop out.’ Stanford scholar Ken Kesey was involved in hallucinogenic research and later formed tours with his ‘merry pranksters’ promoting hallucinogens. Psilocybin, and a host of other hallucinogens, quickly became the hallmark of counter culture and a younger generation was experimenting with mushrooms recreationally.  These drugs were often used during musical festivals such as Woodstock and Grateful Dead concerts and users were stereotyped as ‘hippies’ or ‘druggies’ and were also considered to be dregs of society. By the late 1960s, a backlash against the perceived corrosive effects of hallucinogens on the values of western middle class America resulted in the United States Drug Enforcement Administration (DEA) to conclude, such drugs “produce no aphrodisiac effects, do(es) not increase creativity, (and) has no lasting positive effect in treating alcoholics or criminals” (DEA, 1970) and were later criminalized under the Nixon Administration in the 1970s. These actions helped create a negative view of psilocybin and stifled beneficial research.

The resurgence of Psilocybin Research

Research into the potential health benefits of hallucinogens to treat mental health conditions has undergone a modern-day renaissance. Ronald Griffiths of John Hopkins University is considered by many to be the grandfather of current psychedelic research and he is a clinical pharmacologist who has conducted a series of studies funded by the U.S. government on psilocybin. One of his more recent studies involved the use of psilocybin to treat depression (Griffiths, et. al., 2016). Other prominent researchers have confirmed Griffiths’ findings that psilocybin is associated with a positive effect on depression (Carhart-Harris 2016).  Recent research has shown the drug’s ability to aid in the treatment of alcohol addiction( Bogenschutz, 2015). Several recent studies have also shown psilocybin to be effective in smoking cessation (Cahill, et. al., 2016; Garcia-Romeu, et. al.; and 2014, Johnson, et. al., 2014).

Evidence Supporting Psilocybin as a Treatment for Violent Behavior

New evidence supports the position that psilocybin may curb violent behavior.  In the 1970s, researchers in Poland observed that rodents treated with psilocybin demonstrated less violent behavior compared to a control. (Kostowski et. al., 1972 and Uyeno, 1978). New research regarding psilocybin has shown promise in treating depression, anxiety, and other mood disorders. However, so far very little research has focused on treating violent behavior in humans.

Presently, two prominent researchers have begun examining psilocybin’s potential for treating violent behavior:  Peter Hendricks (Associate Professor at the University of Alabama) and Associate Professor Zach Walsh (co-director for University of British Columbia Okanagan’s Centre for the Advancement of Psychological Science and Law).

The section below outlines their latest studies and examines the methods used in order to understand their limitations and how they might be considered a foundation for future research in using psilocybin as a treatment for violent behavior.

Hendricks, 2014

In 2014, Hendricks led a research study using five years worth of coded interview data on 25,622 monitored parolees from the southeastern United States.  Approximately 70% of the subjects were male having an average age of 31. The main variables were hallucinogen vs. non-hallucinogen usage – the exact type of hallucinogen was not specified. This research can be considered an observational study and not a clinical study. The outcome of interest was supervision failure comprised of parameters including failed court appearance and incarceration. The result reported that hallucinogen use could predict as much as a 40% reduction in supervision failure. Such a percentage is extraordinarily high. While the sample size was very impressive, according to the accepted standard of n=400 (Hosmer & Lemeshow 2000), the use of logistic regression does not require the rigorous assumptions of other inferential statistical methods such as normal distributions within and homogeneity of variance between variables.

Walsh and Hendricks, 2016

In 2016, Walsh and Hendricks (along with other researchers) examined and coded incarceration interview data from 302 inmates in an Illinois prison (Walsh et. al., 2016).  While the sample size is promising, this type of research method can be considered ‘observational’ as the response data was more similar to ‘self-reporting’ and subjects were not part of a clinical study that involved controlled doses and blood measurements etc.  The subjects themselves were all male and were compensated monetarily for their participation in the study. In addition, the primary metric of hallucinogenic use was whether or not a subject had taken any such drug at any point in their lifetime – it did not target psilocybin specifically.  These inconsistencies may have introduced some bias into the findings. Results of the analysis might have also benefited from the inclusion of proportional hazards test for the Cox regression that was used – such as the Kolmogorov-type Supremum Test and the Schoenfeld’s residuals test. The author does admit unmeasured factors, as well as any potential interactions with other drug use, may act as confounders in the findings.

Hendricks, 2017

Just recently, in October of this year, Hendricks completed an ambitious research study involving  13 years worth of coded responses from a survey given 480,000 individuals in the general population (an extremely impressive sample size). Once again, this research is considered to be an observational study and not a clinical case study. Subject responses related to hallucinogens were coded as ‘lifetime classic psychedelic users’ even if they only used it once in their life time. The actual survey asked participants “Have you ever, even once, used psilocybin found in mushrooms?”  Subjects also received a monetary award for participating in the original survey. Results found that psilocybin could predict a 27% reduction in larceny & theft, 12% reduction in assaults, 22% reduction in property crime and an 18% reduction in violent crime.

The researchers admit the results are not as accurate as more controlled studies that examine dose response relationships. They concluded that relationships from the data are associations and not causal relationships. The study also did not examine confounding variables such as interactions with other drugs that may have had an effect. Once again, the use of logistic regression does not require the rigorous assumptions of other inferential statistical methods such as normal distributions within and homogeneity of variance between variables.

Conclusions Regarding Psilocybin as a Means for Treating Violent Behavior

Attempting to test the hypothesis that hallucinogens, such as psilocybin curb, violent behavior is extremely difficult and fraught with confounding variables – as with any human subjects research.  Indeed, all of the authors presented herein admit to limitations in their findings and call for additional research to more fully assess the therapeutic potential of such drugs administered in a controlled, clinical setting.

Logistic regression methods used in these studies is an interesting method, in simplistic terms it can be thought of as a ‘look back’ in order to see if conditions in the past can be used as a predictor of future behaviors. Nonetheless, these latest studies add to the valuable emerging body of data indicating beneficial effects of hallucinogen interventions and run counter to popular misconceptions that such substances only have harmful effects with no therapeutic benefits.

Sound bites and sensational headlines such as “LSD and Magic Mushrooms Could Beat Domestic Violence” and “Psychedelic drugs may reduce domestic violence” are not completely accurate and are not necessarily helpful in breaking down negative stereotypes still portrayed in society today. Thankfully, research around therapeutic potentials of these substances continues to grow through organizations such as the Multidisciplinary Association for Psychedelic Studies (“MAPS”) and the Heffter Research institute (currently seeking FDA approval of psilocybin to treat cancer patients with emotional distress). It is also worth noting that Mayoral Candidate Kevin Saunders just filled a ballot measure in the state attorney general’s office and hopes to allow Californians the opportunity to vote on a decriminalization initiative for Psilocybin. It is time to apply the methods of scientific rigor from more commonly accepted research into the hallucinogenic arena in order to better understand their benefits rather than their costs to society.


Bogenschutz MP, Forcehimes AA, Pommy JA, Wilcox CE, Barbosa PCR, Strassman RJ. Psilocybin-assisted treatment for alcohol dependence: a proof-of-concept study. J Psychopharmacol 2015;29:289–299. doi:10.1177/0269881114565144

Carhart-Harris RL, Bolstridge M, Rucker J, Day CMJ, Erritzoe D, Kaelen M, Bloomfield M, Rickard JA, Forbes B, Feilding A, Taylor D, Pilling S, Curran VH, Nutt DJet al., 2016, Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study, LANCET PSYCHIATRY, Vol: 3, Pages: 619-627, ISSN: 2215-0374.

Cahill K, Lindson-Hawley N, Thomas KH, Fanshawe TR, Lancaster T. Nicotine receptor partial agonists for smoking cessation. Cochrane Database Syst Rev. 2016 May 9; (5):CD006103. Epub 2016 May 9.

DEA Public Affairs (1970). “DEA – Publications – LSD in the US – The Drug” Archived from the original on 1999-04-27. Retrieved 2010-04-20.

Garcia-Romeu A, Griffiths RR, Johnson MW. Psilocybin-occasioned mystical experiences in the treatment of tobacco addiction. Curr Drug Abuse Rev. 2014; 7(3):157-64.

Hendricks PS, Clark CB, Johnson MW, Fontaine KR, Cropsey KL (2014). Hallucinogen use predicts reduced recidivism among substance-involved offenders under community corrections supervision. J Psychopharmacol. Jan; 28(1):62-6.

Hendricks PS1, Crawford MS, Cropsey KL, Copes H, Sweat NW, Walsh Z, Pavela G. (2017). The relationships of classic psychedelic use with criminal behavior in the United States adult population. J Psychopharmacol. Oct 1:269881117735685.

Johnson, R.R., Carducci, M.W., Umbricht, M.A., Richards, A., Richards, W.A., Cosimano, B.D., and Klinedinst, M.P. (2016). Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. Journal of Psychopharmacology, 30(12), 1181-1197.

Johnson MW, Garcia-Romeu A, Cosimano MP, Griffiths RR. Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. J Psychopharmacol. 2014 Nov; 28(11):983-92. Epub 2014 Sep 11.

Kostowski W., Rewerski W., Piechocki T. (1972) II. The effects of some hallucinogens on aggressiveness of mice and rats. Pharmacology  7:259–263.

Uyeno ET (1978) Effects of psychodysleptics on aggressive behavior of animals. Mod Probl Pharmacopsychiatry  13:103–113.

Zach Walsh, Peter S Hendricks, Stephanie Smith, David S Kosson, Michelle S Thiessen, Philippe Lucas, and Marc T Swogger (2016). Hallucinogen use and intimate partner violence: Prospective evidence consistent with protective effects among men with histories of problematic substance use. Journal of Psychopharmacology, Vol 30, Issue 7, pp. 601 – 607.

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