In a retrospective survey of 151 primarily US veterans who attended psychedelic-based treatment, participants reported a significant rise in active belief in God or a higher power and a decline in explicit non-belief after their most memorable psychedelic experience, with no significant change in formal religious or spiritual affiliation but qualitative shifts in their relationship to spirituality. These results suggest psychedelics can catalyse increased spiritual connection and reorientation, especially among prior doubters or nonbelievers.
The acute effects of psychedelic medicines include shifts in perception and awareness that can often include mystical or spiritual elements. Research suggests that these experiences can also extend into more persisting changes in spirituality, yet this area is underexplored. This study examined the effects of psychedelic experiences on spiritual beliefs using a survey of N = 151 people who had received funding to attend a psychedelic-based treatment. Participants were primarily United States (US) veterans who retrospectively completed an online survey assessing the impact of their most memorable psychedelic experience on thoughts, emotions, and behavior. When comparing beliefs reported after one’s most memorable psychedelic experience with those reported before, the proportion of participants who endorsed an active belief in God or a higher power was significantly higher, and the proportion who denied a belief in God or a higher power was significantly lower. We did not observe significant changes in affiliation with spiritual or religious groups after the psychedelic experience, but qualitative analysis suggested that the nature of the participants’ relationship with spirituality exhibited some shifts. These findings suggest that psychedelic experiences can act as a catalyst for increased spiritual connection and reorientation, particularly among individuals who previously identified as doubting or nonbelieving.
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.
Papers cited by this study that are also in Blossom
Alper, K. · The Alkaloids Chemistry and Biology (2001)
Andrews, T., Wright, K. · Sociology Compass (2022)
Barrett, F. S., Johnson, M. W., Griffiths, R. R. · Journal of Psychopharmacology (2015)
Brown, T. K., Alper, K. · The American Journal of Drug and Alcohol Abuse (2017)
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.
The current study aims to determine whether psychedelics are associated with altered spiritual beliefs and religious a liations in veterans, based on retrospective responses to a survey about their most memorable psychedelic experiences. Our study is also uniquely positioned to provide information on ibogaine, given that most participants reported on an experience with ibogaine. Our primary hypotheses were: 1) The proportion of participants who endorsed active belief in and pursuit of a relationship with God or a higher power will be higher after the most memorable psychedelic experience, and 2) The proportion of participants who denied belief in God or a higher power will be lower after the most memorable psychedelic experience. We also proposed secondary hypotheses that the proportion of participants endorsing a liation with 1) organized religion, and 2) Christian religion, will be lower after the most memorable psychedelic experience (Christianity is the organized religion with highest representation in the current sample).
Veterans Exploring Treatment Solutions VETS: Veterans Exploring Treatment Solutions, Inc. (VETS) is a 501(c)(3) non-pro t organization that provides grant funding for Special Operations Forces (SOF) veterans seeking psychedelic-assisted therapy. VETS is not a psychedelic treatment provider, and grants are primarily awarded to SOF veterans (e.g., Navy SEALs, Army Green Berets, Marine RECON) and their spouses. Occasionally, special circumstance grants are awarded on a case-by-case basis to veterans who may not meet SOF distinction but are in immediate need of assistance. Grant recipients are awarded grant funding to attend psychedelic programs in countries where these treatments are legal or unregulated. Psychedelic programs vary in length, clinical approach, and psychedelic substance offered, among other considerations. Grant recipients self-select the psychedelic program they wish to attend. Despite the availability of disparate psychedelic programs, most VETS grant recipients pursue ibogaine-assisted therapy in conjunction with 5-MeO-DMT.
All VETS grant recipients who had completed a psychedelic program were eligible to participate in the survey. Beginning in November 2023 and continuing through February 2025, ve email campaigns invited 659 total grant recipients to participate. Email communications described the survey as an effort to better understand the religious and faith experience of grant recipients in order to inform organizational programming and policy development. No compensation was provided, but participants were invited to enter a ra e for VETS merchandise. The survey was anonymous, unless respondents provided an email to be entered into the ra e. The link to the survey was also posted on the VETS community platform, a private webspace available to grant recipients to access programming, network, and communicate with peers and organizational staff. VETS staff members also encouraged survey participation by word of mouth during programming. Consent for anonymized release of survey responses and testimonial data was collected prior to survey participation when participants were awarded their grants through VETS.
The survey was designed and housed on Jotform, an online survey and workforce platform. Participants accessed the survey using a weblink. The survey took approximately 20 to 40 minutes to complete, depending on responses to free-form questions.
Participants were asked six items gauging demographic information, including age, VETS grant classi cation, marital status, race/ethnicity, and sexual orientation.
Participants were asked about religious a liation and participation in faith-based groups before their most memorable psychedelic experience and at the time of the survey completion. Responses included Lutheran, Methodist, Reformist, Buddhist, Spiritual, Jewish, Baptist, Anglican, Non-denominational Christianity, Hindu, Atheist, Agnostic, Presbyterian, Pentecostal, Catholic, New Age, Muslim, Mormon, Other (open eld), None of the above. Respondents could select multiple options.
Using a ve-item scale (below), participants were asked to describe their belief in God or a higher power before their most memorable psychedelic experience and at survey completion. The scale is not a validated measure. Five-Item Scale: 1) Do not believe in God or a higher power, 2) Doubting in God or a higher power, 3) Searching for God or a higher power, 4) Passively believe in God or a higher power, and 5) Actively believe in and pursue a relationship with God or a higher power. Participants were also asked if their most memorable psychedelic experience brought them closer to God or a higher power, with "yes" or "no" as the response options.
Respondents were asked when their most memorable psychedelic experience was, which psychedelic substances were consumed in that experience, and psychedelic use outside of the most memorable experience.
A ve-item Likert scale (below) was used to assess changes in religious or spiritual emotions, beliefs, and behaviors. A list of the 33 emotions, beliefs, and behaviors can be found in Supplementary Figuresand. Response options for the Likert Scale were: 1) Signi cantly Decreased, 2) Decreased, 3) No Change, 4) Increased, and 5) Signi cantly Increased.
Respondents were invited to share testimony relating to how their experience has affected their faith or spiritual beliefs. Please see Supplementary Material for a description of additional survey items not included in the analysis. These items were excluded in order to focus on the main outcomes of interest for this manuscript, as outlined in the registration of hypotheses (doi:10.17605/osf.io/6CGZU). Additionally, several items had insu cient endorsement to yield meaningful results (e.g., changes in addiction behaviors were excluded from analyses due to low response).
Given the nature of data collection, steps were taken to screen the data for duplicate entries (i.e., multiple completions of the survey by the same participant). Screening for duplicates was undertaken using a sliding window (review of data from participants from current age +/-1 year). Data entries were compared across the following categories: age (at survey submission), veteran status (veteran, spouse of a veteran, or other), gender, race, sexual orientation, date of most memorable psychedelic experience, estimate of lifetime use of psychedelic substances (+/-5), marital status, spiritual/religious a liation before most memorable psychedelic experience, alcohol or drug use dependencies/behavioral addictions before one's most memorable psychedelic experience. This screening process identi ed six instances of potential duplicate entries (there were no instances of exact matches across any two survey responses, but these cases shared enough information to ag). Sensitivity analyses were conducted excluding the second response from each potential-duplicate pair of items.
Responses to the survey items indexing a liation with spiritual or religious traditions were available for all N = 151 respondents. To facilitate data visualization, we combined related sub-categories into broader categories. Speci cally, the 19 original categories were consolidated into a smaller set of 7, as follows: 1) Buddhist, 2) Non-denominational Christian, 3) Christian (Lutheran, Methodist, Reformist, Baptist, Anglican, Presbyterian, Pentecostal, or Catholic) 4) Spiritual, 5) Agnostic-Atheist (Atheist, Agnostic, write-in response of "questioning"), 6) Other (none of the above, other/write-in response, Muslim, Jewish, Mormon, Hindu, New Age), 7) Multiple. Given that the term "spiritual" is often used to describe engagement in any spiritual or religious practice, in cases where both "spiritual" and another option (e.g., "Buddhist", "Christian") was selected, the more speci c a liation was assigned for the analysis. The a liations of Muslim, Jewish, Mormon, Hindu, and New Age were included in the "other" category due to low numbers precluding meaningful analysis. For participants who selected multiple Christian a liations, if non-denomination Christian was among the a liations selected, they were included in the "non-denominational" category (Figure). After the aforementioned processes were carried out, the "Multiple" label was assigned if a participant reported a liations encompassing at least two different categories (e.g., a participant who selected both "Reformist" and "Non-denominational Christian" would be included in the "Non-denominational Christian category; a participant who selected both "Buddhist" and "Non-denominational Christian" would be included in the "Multiple" category). Given the subjective nature of the categorization decisions described above, we conducted a sensitivity analysis of our outcomes in which we excluded participants who were assigned the "Multiple" label (n = 28)
De-identi ed data was shared by VETS with Stanford Brain Stimulation Lab for analysis. Our primary and secondary hypotheses were assessed using McNemar's test (chi-square test for paired samples). Additionally, to further explore changes in proportions from before to after the most memorable psychedelic experience, we used Generalized Estimating Equation (GEE) models to conduct binary logistic regression. GEEs were conducted in R using the geepack libraryand used a logit link function, First-Order Autoregressive correlation structure (AR-1), and robust variance estimation. To explore the impact of psychedelic experiences associated with ibogaine, we reanalyzed our primary and secondary outcomes with the sample restricted to those participants who reported completing the survey questions based on ibogaine use. We also conducted a sensitivity analysis to explore the robustness of our outcomes regarding religious/spiritual a liation. Speci cally, we reanalyzed the data after excluding responses of participants who selected multiple a liations (e.g., Christian and Buddhist; New Age and Muslim). Finally, we conducted exploratory analyses (estimation of mean and spread) of participants' ratings on a 5-item Likert scale indexing changes for 33 emotions, beliefs, and behaviors. Results and discussion from these ndings are available in the Supplementary information. Analyses and data visualization were conducted using R and SPSS. Packages in R included geepack, broom, dplyr, ggplot2, tidyr, and reshape2.
Respondents were invited to share testimony relating to how their experience has affected their faith or spiritual beliefs using the following free-form question: "Please share any testimony relating to how your most personally meaningful psychedelic experience has affected your faith or spiritual beliefs." We performed thematic analysis on responses to this question, following previously established methods. Codes describing meaningful features of the data were generated using (ATLAS.Ti Scienti c Software Development GmbH, 2023), which were automatically grouped into ve categories. Two researchers (K.S. and I.K.) independently searched for themes in the codes and then, through discussion, converged on a nal set of themes.
Participants included N = 151 individuals, consisting of 133 U.S. veterans and 18 spouses or other individuals relevant to the group, who attended psychedelic programs with grant support from VETS. The mean age of participants was 47.2 years (SD = 7.2). The sample was predominantly male (n = 129, 85.4%) and largely identi ed as Caucasian/White (n = 127, 84.1%), with smaller proportions identifying as Hispanic/Latino (n = 20, 13.2%), American Indian/Alaska Native (n = 6, 4.0%), Asian/Filipino (n = 5, 3.3%), Black/African American (n = 2, 1.3%), Native Hawaiian/Paci c Islander (n = 2, 1.3%), and Other (n = 7, 4.6%; Table). *Participants could select more than one race/ethnicity; percentages may exceed 100%. Belief in a higher power before and after the most memorable psychedelic experience Responses to the survey item indexing belief in God or a higher power before and after one's most memorable psychedelic experience were available for all N = 151 respondents. To investigate Hypothesis 1, we dichotomized survey responses into "active belief and pursuit of a relationship with a higher power" (hereby referred to as "active belief") versus selection of any other response option (i.e., "passive belief", "doubting in", "searching for", or "do not believe" in God or a higher power). McNemar's test indicated a signi cant change in proportions for endorsement of active belief with the proportion of participants who endorsed belief in a higher power increasing at the after time point ( (1) = 79.012, p < .001). Speci cally, n = 27 participants reported active belief at both the before and after time points; n = 0 before but not after; n = 81 after but not before; and n = 43 participants neither before nor after. A GEE model estimated the odds of endorsing active belief after versus before the most memorable psychedelic experience was 11.5 (95% CI: 6.7, 19.9). McNemar's test also indicated a signi cant change in the proportion of participants who endorsed "do not believe" (hereby referred to as "no belief") in God or a higher power from before to after their most memorable psychedelic experience; a binomial test on discordant pairs was used due to a small number of counts across some discordant cells rendering the chi-square test unreliable (p < .001, two-sided statistical test at α = .05). Speci cally, n = 2 participants reported no belief before and after; n = 19 before but not after; n = 0 after but not before; and n = 130 neither before nor after. A GEE model estimated the odds of endorsing no belief after versus before the most memorable psychedelic experience at .08 (95% CI: .02, 36; i.e., the odds of endorsing "no belief" were 12.5 times lower at the after time point). Sensitivity analyses found consistent outcomes for the two analyses described above (i.e., change in active belief and change in no belief) when responses identi ed as potential duplicates were excluded. The McNemar's tests for changes in proportion of participants endorsing belief in God or a higher power were rerun in a sample restricted to participants who had taken ibogaine (or ibogaine + 5-MeO-DMT) during their most memorable psychedelic experience (n = 104 participants). Outcomes remained the same in this subsample. Speci cally, McNemar's test indicated a signi cantly higher proportion of participants endorsing active belief after compared to before their most memorable psychedelic experience ( (1) = 52.019, p < .001). McNemar's test (using binomial test on discordant pairs) also indicated a signi cantly lower proportion of participants who endorsed no belief after compared to before their most memorable psychedelic experience (p < .001, two-sided statistical test at α = .05); speci cally, from before to after the most memorable psychedelic experience, 14 participants shifted from endorsement of "no belief" to another selection, and no participant shifted from another selection to "no belief". See Supplemental Figurefor counts of participants selecting each pair of responses at the before and after time points. Although responses were binarized for the use of McNemar's statistical test, the full range of responses endorsed before and after one's most memorable psychedelic experience are presented in Figure. The most notable pattern appears to be a transition from less to greater belief, as evidenced by darker color in the left-sided columns of Figure. For example, across participants who selected one of the four options other than "active belief" the percentage of participants who transitioned to selecting active belief after their most memorable psychedelic experience ranged from 43% (for those who selected "no belief" before) to 88% (for those who selected "searching for" before). Spiritual/Religious a liation before and after most memorable psychedelic experience To examine our hypothesis that a liation with organized religion would be lower after one's most memorable psychedelic experience, we conducted McNemar's test on a liation with organized religion across the before and after time points. A liation with organized religion encompassed participants who were included in categories 1-3 (Buddhist, non-denominational Christian, Christian) as well as the few participants from category 6 (other) who selected Muslim, Jewish, Mormon, or Hindu (this applied for n = 2 participants at the before time point and n = 1 at the after time point). Lack of a liation with organized religion was assigned for all participants who did not meet the aforementioned criteria. Outcomes from McNemar's test did not support our hypothesis. McNemar's test (using binomial test on discordant pairs) indicated that there was no signi cant change in the proportion of participants endorsing a liation with an organized religious group from before to after their most memorable psychedelic experience (p = .664, two-sided statistical test at α = .05). N = 70 participants endorsed a liation with organized religion both before and after the most memorable psychedelic experience; n = 12 before but not after; n = 9 after but not before; and n = 60 neither before nor after. When this test was repeated in a sample that excluded n = 28 participants who had made multiple a liation selections, outcomes remained the same (p = 1). Speci cally, the proportion of participants who endorsed a liation with organized religion was 46% at both the before and after timepoints. To examine our hypothesis that endorsement of a liation with a Christian religion would be lower after one's most memorable psychedelic experience, we conducted McNemar's test. A liation with Christian religion encompassed participants who were included in categories 2 or 3 (non-denominational Christian or Christian). McNemar's test (using binomial test on discordant pairs) indicated that there was no signi cant change in the proportion of participants endorsing a liation with Christianity (p = .189, twosided statistical test at α = .05). N = 66 participants endorsed a liation with Christianity both before and after the most memorable psychedelic experience; n = 14 before but not after; n = 7 after but not before; and n = 64 neither before nor after. When this test was repeated in the sample excluding n = 28 participants who had made multiple a liation selections (i.e., selected multiple a liations at either the before or after time point), outcomes remained approximately the same (p = .424); speci cally, the proportion of participants endorsing a liation with Christianity was 57% at the before time point and 54% at the after time point. Similarly, when these analyses of the proportion of participants who a liated with organized religion and Christianity were repeated in the subsample that endorsed use of ibogaine associated with their most memorable experience, outcomes were consistent. McNemar's test did not indicate a statistically signi cant shift in proportion of participants endorsing these a liations (p > .05). Figureshows the number of participants endorsing each a liation before and after their most memorable psychedelic experience. This supports more nuanced review of changes in a liation. As can be observed from the intensity of color along the upwards diagonal, the majority of participants seemed to retain the same a liation. The Spiritual category exhibited the greatest increase in a liation after psychedelics. Similarly, the selection "Agnostic-atheist" exhibited a relatively large decrease in selection. While no participants a liated with Buddhism before their most memorable psychedelic experience, several participants selected this a liation after (Please note that there may be additional participants who selected a Buddhist a liation, but who also made other selections and were therefore included in the "multiple" category). Qualitative analysis of self-reported changes in spiritual beliefs 102 participants provided a response available for qualitative analysis. Our qualitative analysis identi ed four themes: 1) Shifts from belief-based to experience-based knowledge of God, 2) Reinterpretation of established religious concepts, 3), Perennialism and love, and 4) The continuity of consciousness after death. Shifts from belief-based to experience-based knowledge of God Participants consistently reported that ibogaine led them to directly experience God, rather than merely believing in God. One participant stated, "I no longer have any need for faith. I now have the knowledge that God is very, very real," while another described becoming "certain there's a creator, a single source that connects us all" following a 5-MeO-DMT experience. This "noetic" quality of their religious experience, felt immediately, authoritatively, and beyond doubt, was often framed as the most consequential aspect of the experience. Participants repeatedly emphasized that this knowledge was gained not through reasoning, scripture, or instruction, but instead through direct encounter (e.g., "I saw God"; "I stood in the presence of the all knowing"). Such reports suggest that psychedelic experiences can transform abstract theological concepts into experiential certainties.
While many participants reported strengthening or restoration of their faith, it also distanced them from religious dogma, authority structures, or exclusive truth claims. As one participant stated, "psychedelics released me from the religious dogma that Christianity places on people" while simultaneously con rming "who God truly is." A few participants described how religious dogma had caused them to lose their connection to God; for example, one participant noted that her strict Catholic upbringing constrained her innate curiosity about spirituality, while another participant reported that the term "God" had begun to carry too much baggage. Both participants reported that their psychedelic experience led them to feel closer to God than ever before, including a sense of God that transcended their preconceived, dogmatic beliefs. According to another participant, "Prior to [my] second [psychedelic] journey, my 'beliefs' were based in religion -which in my opinion is a blueprint for what one 'should' believe. During/after this journey, I've realized theiris no blueprint and there is no 'one' way for faith/spiritual beliefs." In other words, participants described their psychedelic experiences as fomenting a new form of spirituality that does not conform to a rigid structure or set of rules, but can rather be understood as a personal, experiential, and relational process that unfolds outside the boundaries of institutional authority.
Following their psychedelic experience, many participants reported embracing perennialism, the view that all religions are different expressions of the same, underlying truth. Several respondents articulated an expanded theological framework in which religious traditions were understood as culturally speci c expressions of a shared reality rather than competing, incompatible belief systems. Participants experienced the insight that "God is too big for any one faith/religion," for "whatever is out there is much bigger than we can comprehend"; indeed, "all religions -all Gods -all manifestations" are equally valid. While some respondents had an ineffable experience of God during their psychedelic experience, others did describe God as a "uni ed eld of eternal love," "perfect love," or as a being whose "love transcends all things." In other words, psychedelics revealed to many participants that love was not merely an emotional state but rather the foundation of spirituality, the common substrate beneath diverse religious symbols, narratives, and practices. This love was often characterized as "unconditional," "nonjudgmental," and miraculous, fueling the profound psychological transformation and healing that participants experienced on psychedelics. The continuity of consciousness after death Finally, many participants reported a newly consolidated belief in reincarnation or the afterlife, often due to vivid encounters with deceased loved ones or spiritual beings. These experiences were frequently described as resolving long-standing grief, survivor guilt, or existential fear. For example, one respondent described seeing deceased family members who "assured me that they were OK," while another felt a newfound sense of peace following the death of a parent by recalling a vision of "a beautiful, uncapped land where the hand of God was waiting for him." Such experiences often reinforced the perception that death represents a transition rather than an endpoint of consciousness. Notably, these beliefs were again framed as experiential knowledge rather than speculative belief, contributing to a broader sense of existential reassurance and meaning.
Psychedelic experience was associated with increased belief in a higher power Our outcomes indicated a robust shift toward increased spiritual beliefs, coupled with a decline in explicit nonbelief. The odds of endorsing active belief in a higher power after the experience were more than 11 times greater than before (OR=11.5, 95% CI: 6.7-19.9). Notably, no participants who endorsed active belief prior to their experience shifted away from this position afterward. In contrast, explicit nonbelief declined sharply, with the vast majority of participants who reported "no belief" at the before time point transitioning to another belief category. These ndings are consistent with outcomes reported by previous studies assessing belief in God or a higher power across psychedelic use. Speci cally, several quantitative and qualitative analyses have shown that classic psychedelic use is associated with increased belief in a higher power. A notable exception is, which prospectively assessed belief before and after psychedelic use and found no change in belief in a higher power. Additional prospective studies are needed to determine whether this result re ects a true null effect or reduced retrospective bias. Several contemporary studies have con rmed that psychedelics frequently evoke mystical experiences. Qualitative analysis of participant's free responses in the current study indicated mystical experiences were well-represented. For example, participants' descriptions of profound encounters with God or other spiritual beings as well as experiences with a "noetic" quality of connecting with a universal truth are all encompassed under current conceptualization of the "mystical experience". It appears likely that these mystical experiences directly contributed to increased endorsement of belief in God or a higher power following the psychedelic experience. However, the occurrence of mystical experiences and their relationship with spiritual beliefs was not quanti ed in this sample. Aspects of the psychedelic protocols undertaken by many of the participants represented in this survey may have predisposed them towards experiences with spiritual content. The VETS organization supports access for grant recipients to therapists with experience in spiritual integration. Therefore, given that psychedelics appear to amplify the effect of therapeutic context on participant's psyche, these preparatory therapy sessions may have predisposed participants to have spiritual experiences.
Despite a clear increase in belief in a higher power, a liation with organized religion remained largely stable. Neither overall religious a liation nor Christian identi cation demonstrated statistically signi cant shifts. Most participants retained their original a liation, as re ected by the strong diagonal patterns in the a liation heatmap (see Figure). Outcomes from previous studies regarding changes in spiritual or religious a liation following psychedelic use have been mixed. For example,presented results from two large-sample survey studies; the rst study found evidence of an association between psychedelic use and a greater likelihood of transitioning away from religious a liation, but the second study did not replicate this nding. A qualitative study byfound evidence for two paths of deepening spiritual connection: 1) increased closeness to one's faith tradition of origin, or 2) increased spiritual connection accompanied by distancing from organized religion. We did not observe evidence for the latter in our analysis, but it is possible that in larger studies these patterns may be observable in different subsamples of participants. It is also notable that the qualitative analysis of our sample discovered a theme of increased personal connection with God or a higher power that was felt to supersede institutional dogma, which, as noted above, is consistent with classical accounts of mystical experience. Our qualitative outcomes suggest that the increased belief in God or a higher power observed in quantitative analyses was driven by reinforcement of a personal connection with one's faith, as opposed to by reinforced attachment to religious doctrine. Despite the absence of signi cant change in spiritual a liation, several lines of evidence suggest one's most memorable psychedelic experience may be associated with a more expansive spiritual a liation. Speci cally, the heatmap tracking a liation before and after one's most memorable psychedelic experience (Figure) shows an increase in the proportion of participants who endorsed "Spiritual" and "Buddhist" from before to after their most memorable psychedelic experience, while explicit Christian a liation showed only modest net change (Note: we include discussion of Buddhism alongside "Spiritual", as Buddhism is generally considered to be a non-dogmatic religion; additionally, versions of Buddhism practiced in the US tend to emphasize a spiritual but not religious philosophy and way of life;. However, we must note that formal statistical testing of this pattern was not conducted. Additional evidence for increased expansiveness of spiritual a liation following psychedelic experience emerges from the qualitative analysis. This analysis noted a theme of "perennialism", or belief in a shared universal truth that traverses categories of religious a liation, in participants' free-form survey responses. These outcomes are consistent with the notion that salient spiritual experiences can preferentially reshape beliefs about the sacred, without necessarily prompting changes in institutional or identity-based religious a liation. Overall, our ndings align with the idea that psychedelic experiences facilitate spiritual expansion rather than religious conversion.
Given that the majority of participants in this study (69% of the sample) based on experience with ibogaine or + 5-MeO-DMT, we examined our primary outcomes in this subsample. The main patterns outlined above were also observed in this group, namely 1) increased endorsement of belief in a higher power and decreased endorsement of no belief, and 2) lack of signi cant change in identi cation with organized religion or Christianity following one's most memorable psychedelic experience. The trend of increased belief in a higher power is consistent with ndings from a recent qualitative analysis of narrative self-reports from 30 Special Operations Forces veterans who underwent ibogaine treatmentNote: there may be some overlap in sample participants acrossand the current study.). The narratives reviewed infrequently included elements consistent with mystical experiences, including interactions with a divine presence. The ibogaine experiences appeared to facilitate healing through profound experiences of forgiveness, compassion, and restoration of meaning. Overall, the participant's experiences during ibogaine were rich in spiritual content and appeared to play a meaningful role in the therapeutic effects that followed. The association between ibogaine treatment and increased spiritual connectedness in this majorityveteran sample suggests exciting potential for the treatment of moral injury. Moral injury describes a set of effects that can follow perpetrating and/or witnessing actions that violate ones deeply held values; it is associated with increased distress, suicidality, and social withdrawal. Recent estimates suggest approximately one third of combat veterans have experienced at least one potentially morally injurious event. Moral injury is inextricably linked with spirituality, and spiritual support appears to be an integral part of effective treatment. In other words, ibogaine appears capable of supporting spiritual healing in combat veterans, a group at high risk for moral injury. This is especially exciting given recent evidence for profound effects of ibogaine treatment on mental health and TBI-related disability of combat veterans. Future studies will be needed to validate this putative relationship between experiences under ibogaine and healing of moral injury, as well as to explore how spiritual healing interacts with general clinical improvement.
Taken together, our ndings support models experiences acting as catalysts for spiritual reorientation, particularly among individuals who previously identi ed as doubting or nonbelieving. Rather than producing a strong association with organized religion, psychedelic experiences appear to foster a sense of connection, transcendence, and existential meaning that participants interpret within their existing or newly developing spiritual frameworks. Additionally, psychedelic-associated belief change is better conceptualized as a transformation in how spiritual meaning is constructed and experienced, rather than what formal religious identity is endorsed. These ndings carry clinical implications as spiritual changes may represent meaningful components of therapeutic response, especially in scenarios marked by hopelessness, existential distress, or moral injury. Because psychedelics tended not to change religious a liation in this survey, our results may alleviate concerns among clinicians, religious communities and the public that psychedelic therapies inherently undermine religious identity, promote ideological conversion, or erode faith. Instead, our data suggests that profound psychedelic experiences tended to support personal spiritual exploration, while largely preserving preexisting religious identities. This distinction may be relevant for the responsible integration of psychedelic-assisted therapies in culturally and religiously diverse populations. Future prospective studies will be critical for clarifying the durability of these changes, their relationship to clinical outcomes, and the ways in which preparation, integration, and cultural context shape the interpretation of spiritual experiences.
Several limitations warrant consideration. First, belief and religious a liation were assessed retrospectively, raising the possibility of recall bias or post-hoc reinterpretation of pre-experience beliefs. Prospective designs that assess belief and spirituality both before and after psychedelic experiences are needed to avoid retrospective bias. Second, the sample was self-selected, consisting of individuals who voluntarily participated in the program. These individuals may be more predisposed to reporting meaningful or positive psychedelic effects than the general population. We also note that the survey process prioritized anonymity over veri ed responses; speci cally, survey recipients had the option to remain fully anonymous (i.e., not enter email address for ra e participation), which may have facilitated more honest responding, but at the cost veri ed responses. In other words, is possible that recipients entered duplicate responses or even forwarded the survey to non-intended recipients. The observational design of the current study precludes causal inference, and unmeasured contextual factors such as set, setting, cultural background, or integration practices, may have in uenced reported changes. Additionally, the categorical nature of belief and a liation measures may obscure more nuanced shifts in belief intensity or spiritual practice. Regarding the qualitative analysis, while rich and informative, qualitative analyses are inherently interpretive and may be in uenced by analytic framing. Although thematic patterns among participants' narrative responses were consistent and conceptually coherent, these responses may re ect culturally idiosyncratic views on spirituality. Finally, the durability of reported belief and spiritual changes remain uncertain. The present study did not systematically assess long-term stability of belief change, leaving possibility that some shifts may attenuate or evolve over time Future Directions research would bene t from prospective, longitudinal designs, inclusion of validated multidimensional spirituality measures, as well as qualitative interview-based studies of experience both before and after psychedelics. Future studies should also examine how speci c features of psychedelic experiences such as mystical-type phenomena, emotional intensity, or perceived insight relate to subsequent spiritual belief change. Longitudinal studies assessing durability of these changes, their relationship to mental health outcomes, and their interaction with cultural or religious context shape the interpretation and integration of psychedelic experiences, as well as the acceptability and ethical implementation of psychedelic-assisted interventions across diverse populations. Such work may help identify contexts in which spiritual change is experienced as supportive rather than disruptive and inform culturally sensitive clinical practices. Clinically, understanding how spiritual transformations intersect with therapeutic bene t may help inform ethical guidelines for psychedelic-assisted interventions.
FigureLevel of belief in God or a higher power reported before and after one's most memorable psychedelic experience. Numbers in gure re ect the number of participants endorsing each set of Before/After responses (e.g., in the top left corner, 9 participants selected "No belief" at the before time point and "Active belief" at the after time point). The tile colors indicate the percentage of participants from each row (i.e., each "before" response selection) who selected each response at the after time point. (e.g., in the top row, out of 21 participants who selected "No belief" at the before time point, 43% (n = 9) selected "Active belief" at the after time point (medium blue) and no participants selected "Doubting in" at the
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