This study (n=26) found that ayahuasca decreased convergent thinking (a part of creativity) on very experienced participants in an ayahuasca ceremony. The conclusion about divergent thinking (increased) was found on only one of the measures (ratio).
“Introduction Ayahuasca is a South American psychotropic plant tea traditionally used in Amazonian shamanism. The tea contains the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine oxidase-inhibiting properties. Increasing evidence from anecdotal reports and open-label studies indicates that ayahuasca may have therapeutic effects in treatment of substance use disorders and depression. A recent study on the psychological effects of ayahuasca found that the tea reduces judgmental processing and inner reactivity, classic goals of mindfulness psychotherapy. Another psychological facet that could potentially be targeted by ayahuasca is creative divergent thinking. This mode of thinking can enhance and strengthen psychological flexibility by allowing individuals to generate new and effective cognitive, emotional, and behavioral strategies. The present study aimed to assess the potential effects of ayahuasca on creative thinking.
Methods We visited two spiritual ayahuasca workshops and invited participants to conduct creativity tests before and during the acute effects of ayahuasca. In total, 26 participants consented. Creativity tests included the Bpattern/line meanings test^ (PLMT) and the Bpicture concept test^ (PCT), both assessing divergent thinking and the latter also assessing convergent thinking.
Results While no significant effects were found for the PLMT, ayahuasca intake significantly modified divergent and convergent thinking as measured by the PCT. While convergent thinking decreased after intake, divergent thinking increased.
Conclusions The present data indicate that ayahuasca enhances creative divergent thinking. They suggest that ayahuasca increases psychological flexibility, which may facilitate psychotherapeutic interventions and support clinical trial initiatives.“
“Ayahuasca intake significantly modified divergent and convergent thinking as measured by the picture concept task, PCT. While convergent thinking decreased after intake, divergent thinking increased.”
This is however, the paper notes, possibly confounded by the antidepressant effect of MAOIs (used in the Ayahuasca mixture) themselves.
It’s also interesting to note that the participants of the study were very experienced with Ayahuasca.
“Group 1 included 15 participants (10 women) with a mean ± SD age of 37.4 ± 5.8 and 15.5 ± 3.2 years of education. They all had prior experience with ayahuasca, having taken it on an average of 27.5 ± 33.4 occasions. Group 2 included 11 participants (7 women) with a mean ± SD age of 52.0 ± 13.0 and 18.4 ± 1.5 years of education. All had also prior experience with ayahuasca, having taken it on an average of 103.6 ± 152.9 occasions.“
The study is interesting as it studies the acute effects of ayahuasca, but the conclusions stated in the study title are stronger than the data suggest. See table 1 in the paper for all the correlations.