This study aimed to investigate the characteristics of past-year ayahuasca users (who will be referred to simply as ‘ayahuasca users’), their current well-being, their past year problematic alcohol use and their lifetime mental illness diagnoses relative to comparison drug user groups, and the subjective effects of ayahuasca in new users. Given prior observational research with individuals taking the drug in a religious context, we hypothesised that ayahuasca users would have better current well-being and less past year problematic drinking.

In the current study, ayahuasca users reported greater well-being than past-year LSD and magic mushroom users (who will be referred to simply as ‘classic psychedelic users’) and the non-psychedelic using other respondents. Ayahuasca users reported less problematic drinking than classic psychedelic drug users. However, both groups would be considered hazardous drinkers according to the AUDIT cut-off and both groups reported higher greater problematic drinking than the other respondents in this survey. Ayahuasca and classic psychedelic users were also more likely to report lifetime diagnoses of mental health problems than other survey respondents.

We also examined the subjective effects of ayahuasca in people whose most recently taken new drug was ayahuasca. The modal and median duration of effect of ayahuasca was 6 hours and the modal and median time to peak effect was 1 hour. Generally, compared to LSD and magic mushrooms, ayahuasca was rated as: stronger; less pleasurable; having more negative effects while high; having weaker ‘comedown’ effects after use; creating less of an urge to use more; and having less risk of harm following a session of use. Ayahuasca users were more likely to live in countries in South America, particularly Colombia (n = 66) and Brazil (n = 46). The vast majority of new ayahuasca users ingested the drug via swallowing or drinking, and most acquired the drug from a shaman or a ‘healer’. Across the whole survey, ayahuasca use was also substantially less common than use of LSD or magic mushrooms. However, it is important to note that the survey was self-selecting and so these values do not reflect true estimates of the proportions of people worldwide who use these drugs.

Self-rated psychological well-being was better in ayahuasca users than either classic psychedelic users or other respondents in the survey. This finding fits with previous studies that have found beneficial effects of ayahuasca use on subjective well-being13,22. It is of particular interest that ayahuasca users had better well-being than classic psychedelic users. DMT (the main active compound in ayahuasca), LSD and psilocybin (the active compound in magic mushrooms) all cause their psychedelic effects primarily via agonism of the 5-HT 2A receptor23,24. Therefore, some other pharmacological difference, perhaps due to the non-DMT compounds in ayahuasca; a difference in the way the drugs are taken; or a pre-existing difference in the kinds of people who use ayahuasca compared with LSD and magic mushrooms, may explain this finding. The ceremonial nature of ayahuasca consumption, and the supporting community, may contribute to its positive effects on well-being. Interestingly, these data do not replicate findings that the use of classic psychedelic drugs is associated with greater well-being in the long-term25,26, as this effect was not observed in the classic psychedelic users compared to other respondents. This may well be a result of confounding factors, such as additional drug use and pre-existing differences between classic psychedelic drug users and the other respondents in this survey. Furthermore, in Griffith et al.’s studies, participants are usually hallucinogen-naïve, often report regular participation in religious or spiritual activities, are screened for mental health problems, are prepared before drug administration, are followed during and after drug effects, and the drug is administered in a controlled, laboratory environment under comfortable, supportive conditions. These characteristics may reduce adverse reactions, and are usually not present in uncontrolled settings.

This study also found a higher incidence of lifetime mental health problems in both ayahuasca users and classic psychedelic users, compared to the non-psychedelic other respondents. A previous study of ayahuasca users from Brazil, who were using the drug in a religious context, found lower self-rated psychopathology maintained over one year compared to non-drug using controls13. A limitation of our study was that current mental health diagnoses or psychopathology was not measured, so we cannot distinguish between rates of current or resolved mental health conditions. It may be that people who use more drugs, more frequently (i.e. the ayahuasca and classic psychedelic user groups engaging in poly-drug use) are likely to have more lifetime mental illness diagnoses than those who use less drugs, less frequently (i.e. the other respondents), unrelated to ayahuasca consumption. This could be a result of mental illness preceding poly-drug use, or a result of poly-drug use preceding mental illness diagnosis. An alternative explanation for this relationship may be that people who have or have had mental health problems may be trying or have tried ayahuasca and/or other psychedelic drugs as an unconventional treatment.

When we stratified by country of origin (with or without historical ayahuasca use), we found that lifetime mental health diagnoses were no different amongst users from countries with a history of ayahuasca use. Contrastingly, in those countries without traditional or religious ayahuasca use, people who used ayahuasca had a higher incidence of lifetime mental health diagnoses than either classic psychedelic users or other drug users. We might speculate that different kinds of people may be attracted to ayahuasca for different reasons in countries with and without historical ayahuasca use. For instance, in countries where ayahuasca has been historically used and is more socially accepted today, the experience may be considered more normal and therefore appeal to the mainstream. In contrast, in countries in which it is illegal to possess, use must be clandestine and confined to certain sub-cultures. People who engage in such illicit behaviours are more likely to have lifetime mental health diagnoses, which may contribute to our finding. Previous work has examined the impact of cultural context on the response to drugs and expectation of their positive and negative effects27. The expectation of negative effects from a drug is likely greater in a country where narratives of psychedelic experiences as therapeutic are largely absent28; this could in turn drive more negative psychedelic experiences and possibly contribute to mental health problems.

Ayahuasca has recently emerged as a promising treatment for depression29, and longitudinal studies of users have found lower incidence of mental health issues associated with use of the drug13. In countries without a history of ayahuasca use, we found a higher incidence of lifetime mental illness diagnoses in the ayahuasca users compared with the classical psychedelic users and other respondents. However, we did not measure current mental health issues and so we cannot know whether ayahuasca use is associated with more or fewer current mental health problems. Future research should establish the direction of causality, i.e. are those with mental health problems drawn to seek out ayahuasca as a potential treatment? This explanation is congruent with the majority of the participants in this study reporting taking the substance in a healing context, from a shaman or other spiritual healer. If this were the case, it would not be incompatible with our finding of higher current ratings of well-being in the ayahuasca using group, relative to the other groups. However, future longitudinal studies are required to fully address this question.

Problematic drinking, as measured by the AUDIT, was less prevalent in ayahuasca users than the group using classic psychedelics. This is an interesting finding, as classic psychedelic users were similar to ayahuasca users in many other respects, and is concordant with previous observations of a reduction in substance use with regular ayahuasca use30. However, ayahuasca users did show greater problematic drinking than non-psychedelic using respondents in the sample. Moreover, although the groups were statistically different on this variable, the mean differences were relatively small. Whilst in this study it was necessary for us to compare our ayahuasca users to this broad and heterogenous sample of drug users, future work should aim to match more closely a comparison group. There were differences in drug use across these samples, such that the ayahuasca and classic psychedelic users consumed more substances in the previous year than the other respondents did. Therefore, given people who take ayahuasca are, on average, more likely to use many different drugs than the other respondents (as shown in Table 2), it is perhaps unsurprising that they have higher problematic drinking levels. Since ayahuasca appears to have anti-addictive potentials, which appear to be especially significant for alcohol30, this result could alternatively suggest that users could be seeking ayahuasca to treat their alcohol-related problems, but it is not possible to explore these interpretations due to our cross-sectional design. In order to examine the effects of ayahuasca use on alcohol use disorders more carefully, large longitudinal surveys and randomised controlled trials must be employed.

Ayahuasca produced a low urge to use the substance again, which is in agreement with previous findings10. In comparison to the classic psychedelics, themselves of a low-abuse potential31, ayahuasca engendered less desire to take more of the drug. These findings suggest that ayahuasca has a very low abuse potential, which speaks to its safety as an emerging treatment for depression, anxiety and drug addiction. Ayahuasca was rated as having stronger negative effects while high than LSD or magic mushrooms, and these differences were the largest observed. This may well be related to the well-known vomit-inducing effects it has. Interestingly, ayahuasca was rated as being stronger, but also less pleasurable. One might speculate that the ayahuasca experience is cultivated to be less about ‘pleasure’ and more about meaning, spirituality and learning, than LSD and magic mushrooms, which are frequently taken in a recreational way.

Strengths and Limitations

One important strength of this study was the use of an international sample of drug users, making this the largest characterisation of ayahuasca use to date, and in the most demographically broad sample. This study, unlike previous work, was not confined to individuals who take the drug alongside membership of a syncretic church, and therefore did not confound the effects of the drug with the non-specific effects of being part of a specific religious organisation. Most importantly, our survey was self-selecting and so was not representative of the global population or the drug-using global population. Therefore, the conclusions we draw may not extend to all ayahuasca and classic psychedelic (LSD and magic mushroom) users. Moreover, we were reliant on self-report data and are unable to confirm the substance ingested was indeed ayahuasca, although the relatively large agreement in the profile of effects would suggest this was the case. It would have been useful to have data on number of lifetime ayahuasca sessions; we would then have been able to explore associations between extent of ayahuasca use and our outcomes. However, because the Global Drug Survey has a very large number of questions, questions about lifetime drug use were sacrificed in order to not overburden the respondents. Another limitation of the current study was that mental illness diagnoses were only measured over the lifetime, so it was not possible to discern current from resolved mental health problems. Future studies should therefore measure this variable.