Feeling connected may explain why psilocybin retreats lift wellbeing for a year, study suggests

A year-long study of people attending guided psilocybin retreats has found that participants reported substantial improvements in mental wellbeing that largely persisted for twelve months, and that the strongest statistical link to those gains was a heightened sense of connectedness — to themselves, to others, and to the world around them. The research, published in Frontiers in Psychiatry, followed 173 adults who took part in a structured retreat program run by licensed Swedish psychologists in the Netherlands, where psilocybin truffles are legal to ingest.

The study was naturalistic rather than experimental: there was no control group, no placebo, and no blinding, so the observational design precludes any causal inference. Participants self-selected into the retreat, paid roughly SEK 27,000 (about USD 2,600) for the program, and completed seven online surveys from two weeks before the retreat to twelve months afterward. Mental wellbeing was measured with the seven-item Short Warwick-Edinburgh Mental Wellbeing Scale, a validated instrument that asks how often people have felt optimistic, useful, relaxed, and able to deal with problems.

Statistical models treating time as a categorical variable showed that wellbeing did not change from baseline the day before the retreat, but rose sharply immediately afterward and remained significantly above baseline at every follow-up point through twelve months, with all timepoint comparisons from one day after the retreat onward reaching p < .001. The increase was largest right after the retreat and then settled at a somewhat lower but still elevated level. Notably, participants with lower baseline wellbeing showed the greatest improvements, a pattern the authors caution may partly reflect regression to the mean in the absence of a control group.

Context matters for interpreting the baseline. At the start, only 51.3 percent of participants with valid wellbeing data met the Public Health Agency of Sweden’s criterion for good mental wellbeing, compared with a 2024 Swedish population benchmark of 83.7 percent — a gap that was statistically significant. By three months after the retreat, the proportion had risen to 75.2 percent, still descriptively below the national figure but much closer to it. A sensitivity analysis restricted to people with data at both timepoints showed a similar shift, from 48.1 percent to 74.0 percent, suggesting the improvement was not an artifact of different people dropping in and out of the sample.

To probe what might explain the wellbeing gains, the researchers examined four candidate psychological mediators: connectedness, measured with the Watts Connectedness Scale; spiritual transcendence, from the Spiritual Transcendence Scale; the anxiety facet of neuroticism, from a short IPIP-NEO scale; and absorption, the disposition to become deeply immersed in sensory and imaginative experience. In single-mediator models, all four were associated with wellbeing improvements. But when all four were entered simultaneously, connectedness retained the largest unique indirect effect, accounting for 46.8 percent of the mediated effect, followed by reductions in trait anxiety at 21.3 percent and absorption at 9.4 percent. Spiritual transcendence, which correlated strongly with connectedness and absorption, no longer contributed uniquely once that overlap was taken into account.

The study also measured the intensity of mystical-type experiences — feelings of unity, transcendence of time and space, ineffability, and deeply felt positive mood — using the 30-item Mystical Experience Questionnaire administered the day after dosing. More intense mystical experiences predicted greater increases in connectedness, spirituality, and absorption, and greater reductions in trait anxiety across follow-up. The association between mystical intensity and wellbeing was strongest in the first three months after the retreat and weakened at later timepoints. Critically, when connectedness was added to the model, the link between mystical experiences and wellbeing was substantially attenuated and no longer statistically significant, whereas it remained significant when the other mediators were controlled instead. This pattern suggests connectedness may act as a candidate pathway carrying the effect of the acute experience into longer-term wellbeing.

The retreat program itself was highly structured. It spanned four weeks across three phases: preparation, retreat, and integration. Participants had four individual sessions with a facilitator — one before, two during, and one after the retreat — plus multiple group meetings, including roughly five during the retreat itself. The retreat phase lasted four days in a rural Dutch setting with up to 20 participants per group and three facilitators, at least one a licensed psychologist. Two group psilocybin sessions were held on days one and three, using fresh Psilocybe Hollandia truffles. The first session used a moderate introductory dose (median 20 grams wet weight) and the second a higher dose (median 50 grams) adjusted to the participant’s first-day experience. Psilocybin content was not analyzed but has been estimated at roughly 0.6 to 1.7 milligrams per gram of fresh truffles.

During dosing sessions, participants lay on mattresses arranged in a circle while facilitators provided continuous emotional and psychological support. Structured group exercises before and during the retreat aimed to foster psychological safety, trust, group cohesion, mindfulness, and intention-setting. Afterward, two group integration sessions and one individual session helped participants reflect on their experiences and translate them into everyday life. The authors emphasize that facilitators played a supportive, facilitative role rather than delivering a formal psychotherapeutic intervention, and that the inherently social environment — shared experience, collective meaning-making, interpersonal connection — may itself have been an active ingredient shaping outcomes.

The findings come with substantial caveats. Without a control group, expectancy effects cannot be ruled out: participants paid for the retreat and may have arrived with strong expectations of personal growth. Concurrent therapy, medication changes, or major life events during the follow-up year could also have influenced outcomes. Follow-up completion declined over time, partly because the survey platform unexpectedly closed in late 2024; only 56 of 173 participants completed the twelve-month assessment. Attrition analyses found some selective dropout — lower mystical experience scores and lower trait anxiety predicted non-response at certain timepoints — though re-estimating the primary model with baseline neuroticism included left the timepoint estimates virtually unchanged. Mediators and wellbeing were assessed at the same timepoints, so temporal precedence cannot be established, and all outcomes were self-reported.

The sample also limits generalizability. Participants were predominantly middle-aged (median 49), just over half were women, and 56.6 percent had never used psychedelics before. Depression and anxiety were not exclusion criteria, and psychiatric diagnoses were not systematically assessed, so the sample should not be assumed free of psychological difficulties — which may partly explain the low baseline wellbeing. The authors also note broader concerns in psychedelic research, including publication bias, expectancy effects, and qualitative reports of risks such as psychological destabilization and difficult integration. They stress that the results should not be read as evidence that psychedelic retreats are universally beneficial, but rather that positive outcomes may occur within carefully structured settings with screening, preparation, support during dosing, and integration. Future controlled studies, they argue, are needed to disentangle the relative contributions of the psychedelic substance, the social context, and the surrounding program — questions that matter both for psychedelic science and for the wider public mental health conversation about connection and wellbeing.

Subject of Research: Psychological pathways linking guided psilocybin retreat experiences to sustained mental wellbeing over 12 months

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

Article References: Åkesson, M., Granqvist, P., Johansson, R., & Gruneau Brulin, J. (2026). Connectedness as a candidate pathway linking psilocybin retreat experiences to sustained wellbeing: a prospective naturalistic study. Frontiers in Psychiatry, 17, Article 1924069. https://doi.org/10.3389/fpsyt.2026.1924069

Image Credits: AI Generated

DOI: 10.3389/fpsyt.2026.1924069

Keywords: psilocybin, psychedelic retreats, connectedness, mental wellbeing, mystical experiences, neuroticism, spiritual transcendence, absorption, naturalistic study, public mental health, candidate, pathway