Concord Prison Experiment

The original study involved the administration of psilocybin manufactured by Sandoz Pharmaceuticals to assist group psychotherapy for 32 prisoners in an effort to reduce recidivism rates.

The researchers would administer psilocybin to themselves along with the prisoners, on the grounds of "[creating] a sense of equality and shared experience, and to dispel the fear that often accompanies relationships between [experimenters] and [subjects]".

[2] The results of this experiment have been largely contested by a follow-up study, citing several problems including differences in the length of time after release that the study group versus the control group were compared, and other methodology factors including the difference between subjects re-incarcerated for parole violations versus imprisoned for new crimes.

In his interview within the study, Leary expressed that the major lesson of the Concord Prison experiment was that the key to a long-term reduction in overall recidivism rates might be the combination of the pre-release administration of psilocybin-assisted group psychotherapy with a comprehensive post-release follow-up program modeled on Alcoholics Anonymous groups to offer support to the released prisoners.

Results suggested that hallucinogens may promote alcohol and other drug abstinence and prosocial behavior in a population with high rates of recidivism.