Sub-acute and long-term effects of ayahuasca on mental health and well-being in healthy ceremony attendants: A replication study

This observational study (n=73) replicated an earlier ayahuasca ceremony study, but this time found only improvements in self-reported stress four weeks later, no reduction in depression was observed. The study did also replicate findings of increased life satisfaction the day after the ceremony, which returned to baseline four weeks after.


Background and aims There is a growing body of evidence suggesting that the psychedelic plant tea, ayahuasca, holds therapeutic potential. Uthaug et al. (2018) demonstrated that a single dose of ayahuasca improved mental health sub-acutely and 4-weeks post-ceremony in healthy participants. The present study aimed to replicate and extend these findings. The first objective was to assess the sub-acute and long-term effects of ayahuasca on mental health and well-being in first-time and experienced users. A second aim was to extend the assessment of altered states of consciousness and how they relate to changes in mental health.

Method Ayahuasca ceremony attendants (N = 73) were assessed before, the day after, and four weeks following the ceremony.

Results We replicated the reduction in self-reported stress 4-weeks post ceremony, but, in contrast, found no reduction in depression. Also, increased satisfaction with life and awareness the day after the ceremony, and its return to baseline 4 weeks later, were replicated. New findings were: reduced ratings of anxiety and somatization, and increased levels of non-judging 4-weeks post-ceremony. We replicated the relation between altered states of consciousness (e.g., experienced ego dissolution during the ceremony) and mental health outcomes sub-acutely. The effects of ayahuasca did not differ between experienced and first-time users.

Conclusion Partly in line with previous findings, ayahuasca produces long-term improvements in affect in non-clinical users. Furthermore, sub-acute mental health ratings are related to the intensity of the psychedelic experience. Although findings replicate and highlight the therapeutic potential of ayahuasca, this needs to be confirmed in placebo-controlled studies.

Authors: Kim I. van Oorsouw, Malin V. Uthaug, Natasha L. Mason, Nick J. Broers & Johannes G. Ramaekers


Ayahuasca has been shown to improve mental health in healthy participants sub-acutely and 4-weeks post-ceremony. The present study replicated and extended these findings, and found that the intensity of the psychedelic experience is related to the mental health improvements.


Pharmacological changes can explain the acute effects of psychedelic substances such as ayahuasca, but long-term effects may be related to psychological insights gained during or after the psychedelic experience. Psychological insights, a more positive life stance, and changed worldview are commonly reported outcomes after ingestion of ayahuasca. Ayahuasca drinkers also report improvement in mental and physical health, interpersonal relationships and work.

Psychedelics like ayahuasca may have a therapeutic effect on mental health depending on the psychedelic experience itself, such as increased sense of unity, insight or ego-dissolution participants experienced under the influence.

The present study aimed to replicate and extend findings by Uthaug et al. (2018) by investigating whether a single dose of ayahuasca could elicit sub-acute and long-term improvements in mental health, mindfulness and satisfaction with life in healthy ayahuasca drinkers in a naturalistic setting.

We had no specific hypothesis regarding previous ayahuasca experience, but first-time users might be more anxious and have higher expectations, which may bias subsequent improvements in mental health outcomes.


Data were collected at ayahuasca ceremonies in the Netherlands and Czech Republic. Participants were asked to participate in the study either by e-mail or on site, and the study was approved by the standing Ethical Review Committee.


Seventy-three participants (37 males, 36 females, Mean age 40.54 (SD 5 10.43)) completed the questionnaires of at least pre-and post-measure, and the majority came from Europe. They used ayahuasca for reasons including understanding themselves, solving issues, curiosity, or a combination of these reasons.

Study procedure

Participants were assessed 3 times: at baseline, between 24 h and 2 days after the ayahuasca ceremony, and 4 weeks after the ceremony. The baseline survey was administered online, and the follow-up ayahuasca assessment was administered online.

Ceremonial setting

Ayahuasca ceremonies were conducted in the evenings, starting between 8 and 10 pm and lasting between 6 and 8 h. Participants were provided with a pillow, blanket, bucket, bottle of water and tissue box, and were offered fresh fruit or soup after the ceremony ended.


Several alterations were made to the original test battery administered by Uthaug et al. (2018). The test battery now includes six questionnaires, including measures of anxiety, depression, somatization and altered states of consciousness.

We used the FFMQ-15, SWLS, EDI, and 5D-ASC to assess mindfulness, satisfaction with life, and altered states of consciousness, and focused on Oceanic Boundlesness (OB) and Anxious Ego Dissolution (AED) as predictors of mental health outcomes.

The original study included mostly European and Latin American participants, and there were more likely to be between group differences. The current study included two European samples, and there were no significant differences between the two samples.

Linear mixed model analyses were conducted to investigate the relationship between Session and Experience. First-time and experienced users’ levels of Altered States of Consciousness (5D-ASC) and Ego Dissolution (EDI) were compared using independent samples t-test.


A total of 73 participants completed the baseline, post-ceremony and 4-weeks follow-up measures. Forty-eight participants were new to drinking ayahuasca, and twenty-five experienced users drank 2 times before, 14 drank 3 times or more.

Mental health

A mixed model analysis of DASS-21 data revealed no Session x Experience interaction, or effects of Session for depression or anxiety. A significant Session effect was found for stress, and no Session x Experience interaction was found for self-reported stress.

BSI-18 was used to assess depression, anxiety and somatization. A significant Session effect emerged for somatization ratings, but a significant decrease from sub-acute to the 4 week follow-up was found.

The psychedelic experience: experienced vs first-time users

Participants reported moderate levels of altered states of consciousness on all 5D-ASC dimensions. First-time users did not differ from experienced users on any of the subscales.

Significant positive correlations were found between OB and EDI, OB and the positive subscales of 5D-ASC, and OB and Anxious Ego Dissolution.


The present study investigated the effects of ayahuasca on mental health, satisfaction with life, and mindfulness in 73 attendants of ayahuasca ceremonies in The Netherlands and The Czech Republic.

Ayahuasca reduced long-term stress levels, improved satisfaction with life, and increased mindful non-judging, but not depression levels. Higher levels of Oceanic Boundlessness were related to lower post-ceremony depression ratings, whereas higher levels of Anxious Ego Dissolution were related to higher post-ceremony anxiety and somatization reports.

The presence of AED may have contributed to the lack of sub-acute improvements in mental health, and increased anxiety and distress related somatization symptoms instead. After 4 weeks, anxiety and somatic complaints dropped significantly and were no longer related to the intensity of the psychedelic experience.

We cannot explain why the previously found reduction in depression did not materialize in the present study. However, we did find a negative correlational pattern between self-reported depression and ego dissolution, suggesting that the ayahuasca experience itself may contribute to acute improvements in mental health.

The current patterns of findings suggest that the intensity of the psychedelic experience may be related to ayahuasca’s therapeutic potential, and that higher scores on ego dissolution and oceanic boundlessness could explain long-term reductions in reports of anxiety, stress and somatization. Several studies have shown that surrendering, having a positive mind set, and benefit enhancing strategies such as intention and meditation can help people have a more intense mystical experience under psychedelic use.

The current study has some limitations, such as the lack of statistical power and the lack of a control group. Future studies should include a control group to be better able to isolate the pharmacological effect of the substance. The ayahuasca brew ingested by participants in the present study was not chemically analyzed, making it difficult to interpret whether differences between the two studies are related to chemical differences between the ayahuasca brews.

Study details

Topics studied
Anxiety Depression

Study characteristics
Observational Open-Label Follow-up


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