This talk describes the results of the largest prospective survey of psilocybin use to date, which surveyed participants pre-psilocybin use (N = 1802), and after at 1-3 days (N = 1551), 2-4 weeks (N = 1182), and 2-3 months (N = 657). At the 2-4 week mark, roughly 30% of participants endorsed the experience as being in the top 10 most personally meaningful, spiritually significant, and psychologically insightful experience of their life. 22% met criteria for a complete mystical experience. Few acute negative reactions (<4%) or persisting negative effects (<5%) were reported. At 2-4 week follow-up effect sizes (SMD [95% CI]) of naturalistic psilocybin were medium for depression -0.71 [-0.79, -0.63] (p <.001), with small effect sizes for spiritual wellbeing 0.36 [0.29, 0.42] (p < .001), personal burnout -0.33 [-0.37, -0.29] (p < .001), cognitive flexibility 0.23 [0.15, 0.31] (p < .001), and anxiety -0.21 [-0.28, -0.13] (p <.001). Similar magnitude effects persisted at 2-3 month follow-up. Personality change data are also described and compared to pooled studies of randomized trials. Thus, in this large prospective sample, naturalistic psilocybin use was well tolerated and associated with enduring improvements in mental health and wellbeing.