Dose effect of psilocybin on primary and secondary depression: a preliminary systematic review and meta-analysis

•Psilocybin has a rapid, sizable, and long-term antidepressive effect for primary (major depression patients) and secondary depressive disorder (depressed cancer patients).•Within a certain range, the antidepressive effect of psilocybin decreases and then increases as the dose increases, with 30-35mg/70kg being the most effective dose. Previous studies have shown that psilocybin has antidepressant effects. In the current study, we aim to explore the dose effects of psilocybin on primary (major depression patients) and secondary depression (depressed cancer patients). Published studies concerning psilocybin for depression were retrieved. In accordance with PRISMA guidelines, 6 databases (PubMed, Embase, Web of Science, Cochrane Library, Clinicaltrials.gov 2.3 and WanFang database) were searched for research studies published or still in progress from inception to 30 November, 2020, with language restricted to English and Chinese. Hedges’ g of Beck Depression Inventory (BDI) score changes was calculated as the primary outcome. 7 articles were finally included, with a total of 136 participants. In terms of efficacy, Hedges’ g was 1.289 (95%CI=[1.020, 1.558], heterogeneity I2=50.995%, p