A single 25 mg dose of psilocybin, but not 10 mg, reduced depression scores more than a 1 mg control dose over three weeks in adults with treatment-resistant depression. In this phase 2 trial, 233 participants were randomly assigned to 25 mg, 10 mg, or 1 mg of synthetic psilocybin with psychological support. The 25 mg group showed an average 12-point drop on the MADRS depression scale versus a 5.4-point drop in the 1 mg group, a significant difference. The 10 mg group did not differ significantly from control. Response and remission rates at three weeks supported the primary result, but sustained response at 12 weeks was not significantly different.
Spontaneously recovered, previously forgotten traumatic memories of sexual assaults emerged in two research participants during psilocybin treatment. The authors defend their classification of these experiences as dissociated traumatic memories against criticisms that they lacked corroborating evidence and failed to consider alternative explanations. They further discuss potential therapeutic effects linked to how such experiences are labeled.