The Doctored Results of the Concord Prison Study

Between 1961 and 1963 a group of inmates at the Concord Prison were treated with a combination of therapy and psilocybin - a drug derived from psychedelic mushrooms. They had a much lower recidivism rate. Or so we thought.

One of the more famous studies in psychiatry is the one done on inmates of the Concord Prison in the early 1960s. A group of Harvard researchers, directed by Timothy Leary, treated a group of inmates with psilocybin, a drug derived from hallucinogenic mushrooms. They wanted to find out if hallucinogenic drugs, along with therapy, might make prisoners less likely to commit crimes in the future.

Some time after the release of the group of prisoners, the researchers announced startling results. It was projected that about 64 percent of the prisoners would return after six months. Only 25 percent did. What's more, instead of being incarcerated for new crimes, most were back in prison due to technical parole violations. As Leary continued to follow up with the group of prisoners, the recidivism rate stayed dramatically below the expected level. It looked like psychoactive drugs could make a huge difference in the recidivism rate, and possibly create a more peaceful society.

That cut no ice with the powers that be, and as it turned out, it shouldn't have. A long-term review of the study, done in the 1990s, reveals some liberties taken with the data analysis. Though only some of the records could be recovered, those recovered records are a random sampling of the original group, and can represent the original experiment.

For one thing, it appears that Leary compared the re-incarceration rate of the treated prisoners at 10 months after their release to other groups at 30 months after their release. There is also no evidence that the balance of new crimes to technical parole violations is what Leary claimed it was. He only counted why the people were returned to prison initially - and if they were on parole, they were always recorded as returning to prison due to a parole violation, even if that parole violation was a new crime. It was only later, when they were convicted of the crime, that they were recorded as having been returned to prison due to the crime, not the parole violation. Leary only counted the reason why they first returned to prison, not their eventual conviction for a new crime. So it appears that Leary's results do not prove that drugs keep people out of prison. If only it were that easy.

[Via Dr Leary's Concord Prison Experiment: A 34 Year Follow Up Study.]