Transformative Experience and Social Connectedness Mediate the Mood-Enhancing Effects of Psychedelic Use in Naturalistic Settings
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Transformative experience and social connectedness mediate the mood-enhancing effects of psychedelic use in naturalistic settings Matthias Forstmanna,b,1, Daniel A. Yudkina,c, Annayah M. B. Prosserd, S. Megan Hellere, and Molly J. Crocketta,1 aDepartment of Psychology, Yale University, New Haven, CT 06511; bDepartment of Psychology, University of Cologne, 50931 Cologne, Germany; cSocial and Behavioral Science Initiative, University of Pennsylvania, Philadelphia, PA 19104; dDepartment of Psychology, University of Bath, Bath BA2 7AY, United Kingdom; and eDepartment of Anthropology, University of California, Los Angeles, CA 90095 Edited by Susan T. Fiske, Princeton University, Princeton, NJ, and approved December 17, 2019 (received for review October 24, 2019) Past research suggests that use of psychedelic substances such as predicted mental well-being (4) and proenvironmental behavior LSD or psilocybin may have positive effects on mood and feelings (14), while being negatively related to suicidality (4). of social connectedness. These psychological effects are thought Yet, existing research on the psychological effects of psy- to be highly sensitive to context, but robust and direct evidence chedelics has several important limitations. On one hand, for them in a naturalistic setting is scarce. In a series of field studies laboratory-based approaches, which allow for causal inferences involving over 1,200 participants across six multiday mass gather- through randomization, typically suffer from low sample sizes ings in the United States and the United Kingdom, we investigated due to financial costs and logistical demands. In addition, they the effects of psychedelic substance use on transformative expe- can be affected by sampling bias, in that people may sign up for rience, social connectedness, and positive mood. This approach astudywiththeexplicitdesireto have a psychedelic experience, allowed us to test preregistered hypotheses with high ecological or fail to capture the effects of spontaneous substance use. validity and statistical precision. Controlling for a host of demo- Laboratory settings also rarely resemble settings in which graphic variables and the use of other psychoactive substances, people typically use psychedelic substances—an especially im- we found that psychedelic substance use was significantly asso- portant limitation given that the effects of these substances are ciated with positive mood—an effect sequentially mediated by notoriously affected by situational variables (2). The classic self-reported transformative experience and increased social con- “ ” nectedness. These effects were particularly pronounced for those notions of set and setting emphasize the degree to which who had taken psychedelic substances within the last 24 h (com- intrapersonal and environmental variables can affect the psy- pared to the last week). Overall, this research provides robust chedelic experience (15, 16). Forthisreason,whileexisting evidence for positive affective and social consequences of psyche- laboratory research undoubtedly provides important insights delic substance use in naturalistic settings. into the psychological consequences of psychedelic substance use, this work leaves open the crucial question of how such psychedelic substances | transformative experiences | social consequences manifest in naturalistic settings. Finally, despite connectedness | mood Significance esearch into the therapeutic potential of psychedelic sub- Rstances (such as psilocybin, LSD, and mescaline) has come For millennia, naturally occurring psychedelic substances have into renewed focus after several decades of relatively scant at- been used by indigenous cultures in medicinal or spiritual tention (1). Recent clinical studies attest to the relative safety contexts. Recent scientific investigations hint at the potential and tolerability of these substances (2), in terms of both physical for these substances in the treatment of affective disorders, yet (3) and mental health (4), and contemporary research suggests scientific inquiries into their psychological effects remain that serotonergic psychedelics can have a variety of decidedly scarce. Here we present findings from a large field study of positive effects when used in therapeutic settings. Specifically, mood-related effects of recent psychedelic substance use in clinical researchers have begun investigating the potential of naturalistic settings. We found that recent use of psychedelics was associated with increased positive mood through experi- psychedelics in the treatment of mental health disorders, in- ence of personal transformation and feelings of connectedness cluding affective disorders (5), anxiety-related disorders (6), and to others. Our findings validate recent reports of mood- substance abuse disorders (7). For example, recent findings in- enhancing effects of psychedelic substances in laboratory set- dicate that a single dose of psilocybin, the primary active com- tings and suggest that these effects manifest at least in part Psilocybe ponent in mushrooms of the genus, can meaningfully through changes in the experience of social relationships. attenuate depressive symptoms in patients with treatment re- sistant depression for up to 3 mo postadministration (5). Sim- Author contributions: D.A.Y., A.M.B.P., S.M.H., and M.J.C. designed the study and col- ilar studies have been conducted—or are ongoing—for other lected the data; D.A.Y. edited and provided the final data set; M.F. formulated and N registered the hypotheses, and performed the statistical analyses; D.A.Y. and M.J.C. con- serotonergic psychedelic substances such as LSD (8) or N, - sulted on the analyses; and M.F., D.A.Y., A.M.B.P., S.M.H., and M.J.C. wrote the paper. dimethyltryptamine (found in ayahuasca) (9). The authors declare no competing interest. Researchers have also begun investigating the acute and This article is a PNAS Direct Submission. chronic effects of psychedelic substances on healthy individuals. They found, for example, that serotonergic psychedelics admin- Published under the PNAS license. Data deposition: All data discussed in the paper are available at Open Science Framework, istered in the laboratory have noticeable acute effects on the https://osf.io/avdrc. affective processing of negative stimuli (10), feelings of social 1To whom correspondence may be addressed. Email: [email protected] or exclusion (11), as well as moral (12) and social decision-making [email protected]. (13). Other research endeavors have used large-scale surveys to This article contains supporting information online at https://www.pnas.org/lookup/suppl/ query members of the general public about their substance use doi:10.1073/pnas.1918477117/-/DCSupplemental. history and found that past psychedelic substance use positively First published January 21, 2020. 2338–2346 | PNAS | February 4, 2020 | vol. 117 | no. 5 www.pnas.org/cgi/doi/10.1073/pnas.1918477117 Downloaded by guest on October 2, 2021 being placebo-controlled, participants in laboratory studies are sense of awe or sacredness, and a distinct noetic quality per- aware of the fact they partake in a study investigating the ef- taining to one’s understanding of reality. For example, in a fects of psychedelic substances, which may affect their re- placebo-controlled psilocybin study conducted in a laboratory sponses to questionnaires or tasks due to preconceived notions setting, 22 of 36 participants reported having had such an experi- they might have about these substances. ence after taking psilocybin (23), which 21 participants considered On the other hand, large-scale survey studies, often obtained one of the top five most personally meaningful experiences in their via online sampling, are an efficient way to collect data from a lives (25). These experiences have been found to produce lasting, large number of participants about past psychedelic substance positive effects on subjective well-being (25), openness to experi- use and its psychological consequences. However, interpretation ence (26), perceived meaning in life (25), and prosocial attitudes of these data is complicated by the fact that many participants in and behaviors (19). Importantly, past research found the beneficial these studies were not recently under the influence of the re- effects of psychedelic substance use on subjective well-being spective substances at the time of data collection, thereby ren- depended on the strength of mystical-type experience reported dering their reports subject to the vagaries of personal recollection by participants during the experimental sessions, with more pro- (since participants are often relying on memories of past experi- nounced experiences predicting greater long-term positive out- ences), and are hence potentially unreliable. Research of this comes (27). Therefore, we predicted that people’sreporteddegree nature also suffers from demand and suggestibility effects as of TE as a function of their use of psychedelics would be positively participants are again usually aware they are taking part in a study associated with positive mood. about psychedelics. For these reasons, existing research represents Second, we investigated people’s sense of connectedness to a valuable but incomplete picture of the psychological conse- others. Past research suggests that psychedelics often engender a quences of psychedelic substance use. feeling of ego dissolution (24), a compromised sense of self most likely attributable to attenuated neural connectivity