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

Study details

Topics studied
Anxiety Depression

Study characteristics
Observational Open-Label Follow-up