Psychedelics are associated with changes in spiritual beliefs and orientations in US veterans

The authors situate their study within a recent resurgence of research on psychedelic-assisted therapies, motivated in part by unmet needs among US military veterans for novel treatments for conditions such as treatment‑resistant PTSD and depression. They note that while psychedelic substances have long been embedded in indigenous spiritual traditions, the effects of psychedelic experiences on spiritual and religious beliefs in Western medicalised contexts are underexplored. Prior observational and experimental work has repeatedly reported increases in self‑reported spirituality after psychedelic use, and the phenomenology of psychedelic experiences often includes features—such as ego‑dissolution, noetic certainty, and encounters with sacredness—that are classified in the literature as “mystical experiences”. The authors emphasise that spirituality can influence health outcomes and that understanding psychedelic‑associated spiritual change is relevant both clinically (for populations such as veterans) and sociologically (because community and institutional reactions may shape uptake and integration of psychedelic medicine). They also highlight a relative lack of prior data on ibogaine, a non‑classic psychedelic/oneirogen which many of their participants experienced and which has been linked to potent symbolic and spiritual imagery but carries distinct safety considerations.

Data screening included procedures to identify potential duplicate survey entries by comparing age (±1 year), veteran status, gender, race, sexual orientation, date of memorable experience, estimated lifetime psychedelic use (±5), marital status, prior affiliation, and prior substance‑use dependencies; six potential duplicates were flagged and sensitivity analyses excluded second responses from flagged pairs. Quantitative hypotheses were tested primarily with McNemar's test for paired proportions (pre/post retrospective reports). To model paired binary outcomes and account for within‑subject correlation, the authors also fitted Generalised Estimating Equation (GEE) logistic regression models (logit link, AR‑1 correlation structure, robust variance estimation) in R (geepack). Primary analyses compared endorsement of "active belief" versus other responses and endorsement of explicit "no belief" before versus after the memorable experience. Secondary analyses tested changes in affiliation with organised religion and with Christianity specifically. Subgroup analyses re‑ran primary tests restricted to participants who reported ibogaine (or ibogaine + 5‑MeO‑DMT) for their memorable experience. Qualitative analysis of free‑text testimony followed thematic analysis procedures: responses were coded in ATLAS.ti, codes grouped into categories, and two researchers independently identified and converged on final themes.

Qualitative analysis of free‑text testimony (responses available from 102 participants) yielded four central themes: (1) shifts from belief‑based to experience‑based knowledge of God, where respondents described a noetic, authoritative sense of direct encounter (example quotes: "I no longer have any need for faith. I now have the knowledge that God is very, very real"; "certain there's a creator, a single source that connects us all"); (2) reinterpretation of established religious concepts, with many participants reporting distance from dogma or institutional authority while retaining or deepening a personal connection to God; (3) perennialism and love, in which participants framed religious traditions as culturally specific expressions of a shared underlying truth and described God or the sacred as an expansive field of unconditional love; and (4) continuity of consciousness after death, where vivid encounters with deceased loved ones or spiritual beings led to strengthened beliefs in afterlife or reincarnation and to alleviation of grief or survivor guilt.

The authors acknowledge multiple limitations. Chief among them is retrospective assessment of beliefs and affiliations, which is susceptible to recall bias and post‑hoc reinterpretation; they call for prospective, longitudinal designs with validated multidimensional spirituality measures. The sample was self‑selected and predominantly male and White, limiting generalisability. Survey anonymity precluded verification of responses and may have enabled duplicate or non‑intended entries despite the authors' duplicate‑screening procedures. The observational design prevents causal inference, and unmeasured contextual factors (set, setting, integration practices, cultural background) may have influenced outcomes. The categorical measures used may miss more subtle changes in belief intensity or spiritual practice, and qualitative analyses are interpretive and potentially culturally specific. The authors note uncertainty about the durability of reported changes because long‑term stability was not systematically assessed. They recommend future research that is prospective, longitudinal, incorporates validated measures and interview‑based qualitative work, and examines how features of psychedelic experiences (e.g., mystical phenomena, emotional intensity) and contextual factors shape spiritual belief change and clinical outcomes.