Can psilocybin help rehabilitate prisoners and curb criminal behavior? Image Source: Flickr CC user afgooey74

Can psilocybin help rehabilitate prisoners and curb criminal behavior? Image Source: Flickr CC user afgooey74

One of the most well-known studies in psychedelic therapy is the Concord Prison Experiment. Carried out from 1961-1963, this study set out to determine whether psilocybin (the active compound in “magic mushrooms”) would help reduce recidivism rates in young men who were incarcerated, and whether the effects of psychedelic rehabilitation could be measured. It was a groundbreaking study for its time, and was headed by none other than the psychedelic pioneer Timothy Leary who claimed that overall it was a huge success.

There has been much controversy around the actual results of the study and just how effective psilocybin was in changing inmates’ lives for the better, but rather than suggesting the experiment was a failure, its critics are instead suggesting it be repeated with greater aftercare and a more holistic approach. It is believed that with a better approach, and a more firmly scientific study, the actual effects of psilocybin on recidivism can be better understood, and we will have a fuller understanding of the relationship between psychedelics and behavior.  

The Original Experiment and Results

Dr. Leary and a team of Harvard scientists performed the original study on 32 inmates who volunteered from Concord Prison in Massachusetts. Nearly all of the inmates were approaching their parole hearings, and underwent numerous group therapy sessions and two psilocybin experiences with the research staff. The subjects took a myriad of personality tests at the onset of the experiment and then took them again once it was concluded. Their rate of recidivism would be the ultimate measure of the experiment’s success when compared against the prison’s historical recidivism rate. The methodology of the experiment was somewhat radical in that the inmates were allowed to see the results of their personality tests, choose their dosage level, and even have a say in who among their peers would be involved in group sessions.  

The initial findings of the study seemed phenomenal. Compared to the prison’s historical average of 64%, only 25% of the inmates in the study had returned to prison within six months, and most of them only for parole violations rather than new crimes. The personality tests performed before and after the experiment also showed a measurable benefit to the mental state and well-being of the subjects after taking psilocybin. This was highly encouraging at the time, but in the years after the study, Dr. Leary would be kicked out of Harvard and the cultural attitudes towards psychedelics and their associated research took a big downturn.

Today, as the stigma against psychedelics is waning and new research is being conducted, researchers are reflecting on Leary’s famous study to determine just how effective it was, and how future psychedelic rehabilitation studies might improve on its methods.

A Follow-up Study 34 Years Later

In the late 90s, a new team of researchers sponsored by the Multidisciplinary Association for Psychedelic Studies (MAPS) and headed by Dr. Rick Doblin took a closer look at the Concord Prison Experiment and its long-term effects.  It found that some of the methodologies Leary used in comparing recidivism rates was faulty, in that he was comparing the rates of his subjects after being out of prison for 10 months versus the average rate of recidivism for inmates who had been out for 30 months. Once the data was re-examined by this new team of researchers, it was found that the overall success of the experiment was slight or negligible, rather than hugely significant.

That being said, there is still a lot to learn from the original experiment and how it could be improved on in the future. The prisoners who were administered psilocybin reported mystical and cathartic experiences, and their personal improvement was evident on the personality tests. What Leary and Doblin both lament about the study is that there was very little contact with the inmates after they went on parole, and their inner improvements from the psilocybin could be easily smothered by the enormous social and environmental pressures that they returned to. One of the original test subjects, when interviewed said “I firmly believe that I would never have gone back to prison if I had had help [post-release], if someone would have guided me, taken an interest. Who the hell wants to do time?”[1. Dr. Leary’s Concord Prison Experiment: A 34 Year Follow-Up Study. Rick Doblin. Journal of Psychoactive Drugs; Oct-Dec 1998; 30, 4; ProQuest Medical Library pg. 419.]


While Doblin’s follow-up study did put a damper on Leary’s original findings, it was an important step forward for psychedelic research in showing that hallucinogenic substances like psilocybin can have immense healing potential, but only with the right context and follow-through. This not only strengthens psychedelic research as a whole by accepting rigorous scientific scrutiny, but also begs for a new prison study that integrates the lessons learned from the original experiment. As Dr. Doblin stated, “Whether a new program of psilocybin-assisted group psychotherapy and post-release programs would significantly reduce recidivism rates is an empirical question that deserves to be addressed within the context of a new experiment.”