A long-term follow-up to the Concord Prison Experiment (1961–1963) examined criminal justice records of 21 of the original 32 prisoners who received psilocybin-assisted group psychotherapy. The follow-up found that earlier published claims of reduced recidivism were erroneous. The original researchers had emphasized the need for comprehensive post-release group support, but such services were not sufficiently provided. Whether a new program combining psilocybin-assisted therapy with post-release support could lower recidivism remains an open empirical question.
MDMA given orally to dogs and rats for 28 days caused clinical signs like hyperactivity, dilated pupils, and salivation. Medium and high doses led to significantly less weight gain in both species, with initial decreased food consumption that later reversed. In dogs, reduced testicular size and prostatic enlargement occurred at medium and high doses, with testicular atrophy and prostatic hyperplasia seen microscopically. In rats, some clinical pathology values decreased (urinary pH, blood urea nitrogen, glucose, creatinine, LDH, chloride) while others increased (white blood cell count, phosphorus). No brain lesions were found in either species.