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.
Hallucinations occur in 6-15% of the general population, but their detailed characteristics are poorly understood. In a large online survey of 10,448 participants aged 14-88, auditory hallucinations were most common in the past month (29.5%), followed by visual (21.5%), tactile (19.9%), and olfactory (17.3%); nearly half (47.6%) experienced hallucinations in two or more senses. Many participants rated their hallucinations as severe due to negative content (16.0-31.6%), distress (10.5-16.8%), or dysfunction (12.7-17.3%). Decreased insight occurred in 10.2-11.4%, hypnagogia in 9.0-10.6%, and bereavement hallucinations in 2.8%. Delusions were rare (7.0%) but significantly associated with recent hallucinations. The findings indicate a wide variety of hallucination phenomenology in the general population and support a phenomenological continuum.