Date of Award




Document Type

Master's Thesis

Degree Name

Master of Arts (MA)


Department of Psychology


Clinical Psychology

Content Description

1 online resource (iii, 45 pages) : 1 illustration.

Dissertation/Thesis Chair

Mitch Earleywine

Committee Members

Julia Hormes


Ayahuasca, behavioral activation, depression, hallucinogens, mindfulness, Antidepressants, Mindfulness (Psychology), Behavior therapy

Subject Categories

Clinical Psychology


Ayahuasca, a plant-based hallucinogen that serves as a spiritual medicine in South America, has improved depression in at least one placebo-controlled clinical trial. Case studies suggest that dramatic behavioral changes often follow the Ayahuasca ceremony, but most explanations of antidepressant effects focus on observed changes in mindfulness. The present study investigated if both mindfulness and behavioral activation might also contribute to these anti-depressant effects. We surveyed individuals (N = 152) about their changes in depressive symptoms, Behavioral Activation, and mindfulness after an Ayahuasca experience. Mindfulness was strongly associated with reduced depression severity (r = -.670, p < .001), while behavioral activation was moderately linked (r = -.474, p < .001). Changes in depressive symptoms (Center for Epidemiological Sciences Depression Short Form [CES-D-10]) covaried with subscales from the Five Facet Mindfulness Questionnaire [FFMQ] and Experiences Questionnaire [EQ], confirming previous findings (beta = -.57, [95% CI (- 5.70) - (- 3.25)], p < .001). In addition, a modification of the Behavioral Activation for Depression Scale-Short Form [BADS-SF] accounted for significant unique variance in the improvements in depression (beta = -.16, [95% CI (-6.32) - (-0.08)], p < .05). These results suggest that changes in behavioral activation likely serve as an important mechanism underlying Ayahuasca’s antidepressant effects. Future clinical trials could benefit from tracking behavioral activation. In addition, a concerted focus on increasing valued, positive activities might enhance Ayahuasca’s anti-depressant effects.