Reference: Quevedo, Deborah J. Psychospiritual Integration of an Ayahuasca Retreat Experience. PhD in Transpersonal Psychology. Institute of Transpersonal Psychology, Palo Alto, 2009.
This research was conducted at neo-shamanic ayahuasca retreats in Brazil that were led by a transpersonal psychotherapist. 22 international (English-speaking) retreat participants completed quantitative and qualitative assessments on a confidential website using a repeated measures design. Scales of the Big Five Inventory following participation showed a decrease in Neuroticism (p < .01) and an increase in Agreeableness (p < .05). The Washington University Sentence Completion Test (SCT) was used to measure ego level. SCT scores increased for 36% of the participants (mean increase = 2.13), while for another 36% they decreased (mean decrease = 1.25), and for 27%, results did not show any change. The SCT results suggest that the ayahuasca retreat facilitated growth for those whose SCT scores increased and may have indicated difficulty with integration for those whose SCT scores decreased. Thematic analysis of responses to the qualitative assessments showed that the ayahuasca retreat was, overall, a therapeutic and positive experience for the great majority of participants.
Comment by me:
The research was conducted at the Ayahausca Healing Retreat Center, lead by the Argentinian psychologist Silvia Polivoy, in the coast of Bahia, Brazil (see here http://www.ayahuasca-healing.net/ingles.htm). This center promotes ayahuasca retreats and works also with other plants and techniques, such as lucid dreaming and Salvia divinorum. This is one of the few organizations in the country that are based on a different model than the large matrix of the Brazilian ayahuasca religions (considering in its wide range of lineages, splinter groups etc), working rather on workshop style and being focused mainly to a foreigner public.