Therapeutic effect of an ayahuasca analogue in clinically depressed patients: a longitudinal observational study

This observational study (n=20) assessed depressive symptomatology in clinically depressed patients, using the Beck Depression Inventory (BDI), before attending an ayahuasca ceremony, 1 day, 1 month, and 1 year after. The day after, 12/20 (60%) participants were in remission, which remained up to one year later. Three participants remained mildly depressed ever at 1-year follow-up, while two participants did not respond to treatment.


Rationale: Studies have suggested mental health improvements following the use of the psychotropic plant concoction ayahuasca in non-clinical and clinical samples.

Objectives: The present observational study assessed depressive symptomatology in 20 clinically depressed patients (symptom score > 13 on the Beck’s Depression Inventory) before attendance of an ayahuasca ceremony and 1 month and 1 year after. Secondary measures included ratings of altered states of consciousness and ego dissolution during the ayahuasca ceremony as well as global measures of mindfulness, satisfaction with life, depression, anxiety, and stress.

Results: Twenty participants completed baseline and 1-day follow-up, 19 completed measures at 1-month follow-up, and 17 completed measures at 1-year follow-up. BDI scores reduced from baseline (M = 22.7) to all post-ceremony measures (Ms 11.45, 12.89, and 8.88, for 1-day, 1-month, and 1-year follow-up, respectively). After 1 day, 12/20 participants were in remission (BDI < 13). Remission rates after 1 month and 1 year were 13/19 and 12/17, respectively. Three participants remained mildly depressed (BDI 14–19) at the 1-month and 1-year follow-up. Two participants did not respond and remained at a moderate/severe level of depression at 1-year follow-up. Reductions in the secondary mental health measures and increases in mindfulness and satisfaction with life were found up to 1-year post-ceremony. Improvements in clinical depression and mental health correlated with levels of experienced ego dissolution and oceanic boundlessness during the ceremony up to 1 month after the ceremony. Engagement in additional mental health treatments or use of another psychedelic during study participation may have contributed to improved mental health ratings at 1-year follow-up.

Conclusion: Ayahuasca produces long-term mental health improvements in clinically depressed patients, which highlights its therapeutic potential.”

Authors: Kim van Oorsouw, S. W. Toennes & Johannes G. Ramaekers

Study details

Compounds studied

Topics studied

Study characteristics

20 Humans


Authors associated with this publication with profiles on Blossom

Johannes Ramaekers
Johannes Ramaekers is a professor at Maastricht University his work focuses on behavioral toxicology of drugs and combines methods from psychopharmacology, forensic toxicology and neuroscience to determine drug-induced changes in human performance. Some of this research is done with DMT.


Institutes associated with this publication

Maastricht University
Maastricht University is host to the psychopharmacology department (Psychopharmacology in Maastricht) where various researchers are investigating the effects of psychedelics.