Connectedness as a candidate pathway linking psilocybin retreat experiences to sustained wellbeing: a prospective naturalistic study

Background Psychedelic retreats are increasingly used to promote wellbeing outside clinical settings, yet the psychological processes associated with sustained improvements in wellbeing remain poorly understood. From a public mental health perspective, identifying mechanisms that support positive mental health beyond symptom reduction is of growing importance. Methods This naturalistic longitudinal study followed 173 participants attending guided psilocybin retreats conducted within a structured framework of preparation, dosing, and integration. Mental wellbeing was reported before the retreat and across a 12-month follow-up period. Longitudinal changes were examined using linear mixed-effects models. Mediation analyses investigated whether changes in connectedness, neuroticism (anxiety facet), spiritual transcendence, and absorption were associated with changes in wellbeing. Mystical-type experiences were examined as potential predictors of these psychological changes. Results Participants reported substantial and sustained improvements in mental wellbeing over 12 months, moving from levels below Swedish population norms at baseline toward comparable levels at follow-up. Connectedness showed the strongest statistical association with improvements in wellbeing and accounted for the largest proportion of variance in wellbeing change, followed by reductions in the anxiety facet of neuroticism and absorption. Spiritual transcendence was associated with wellbeing improvements when examined separately but did not retain unique effects in the multiple mediation model. More intense mystical-type experiences predicted greater increases in connectedness, spirituality, and absorption, as well as greater reductions in neuroticism (trait anxiety). The association between mystical experiences and wellbeing was substantially attenuated when connectedness was included in the model, suggesting that connectedness may act as a candidate mediator linking mystical-type experiences to longer-term wellbeing, though the observational design precludes causal inference. Conclusions These findings extend prior work on psychedelic-assisted therapy to naturalistic retreat settings, suggesting that connectedness may represent a key psychological process linking psychedelic retreat experiences to sustained improvements in mental wellbeing. From a public mental health perspective, the results highlight the potential importance of social and relational factors in promoting wellbeing beyond the treatment of mental illness. Future controlled studies are needed to clarify the relative contributions of psychedelic, social, and contextual components.