Research library / Review
The abuse potential of medical psilocybin according to the 8 factors of the Controlled Substances Act
Johnson MW, Griffiths RR, Hendricks PS, et al. Neuropharmacology 2018;142:143-166
This review asks how likely medical psilocybin is to be misused, using the eight factors US regulators weigh when deciding how to schedule a drug. The authors conclude that psilocybin has weak rewarding effects compared with typical drugs of abuse: animals barely self-administer it, and people who use mushrooms illicitly tend to do so only a handful of times. The main risks they identify are dangerous behaviour by people who take it unprepared and unsupervised, and worsening of mental illness in people prone to psychosis. They argue that a medical model, with screening, dose control, preparation, supervision and follow-up, keeps these risks manageable, and suggest Schedule IV if a psilocybin medicine is approved. It is an expert review, not new data, and the scheduling view is a recommendation.
What it found
- Psilocybin has limited reinforcing effects, with only marginal, transient self-administration in animals
- Illicit mushroom use is common but usually limited to a few lifetime occasions
- Main harms are risky behaviour in unprepared, unsupervised users and worsening of psychotic illness in those predisposed
- Authors suggest Schedule IV may be appropriate if a psilocybin medicine is approved