jamie wrote: "Little is known about why people usually initiate the use of ayahuasca, why they interrupt their participation in ayahuasca sessions and whether their experiences were useful in regards to the intention of their use."
There is one really easy way to figure that out...ask them. Humans can be so silly.
The writer refers to reviewed, published research. There are no long term studies conducted about those questions. There is little research data about why some ayahuasca users will stop their use in a ritual context.
The mention of these questions has to do with a previous study, made with members of Santo Daime, and signed by pretty much the same team as this one. They followed regular ayahuasca users for a long time, evaluating long-term psychological changes and potential psycho-pathologies. The results were quite positive, but one limitation remarked by the authors of the study was that they were only evaluating users that had not stopped assisting to Daime ceremonies for a long time. Hence, in the same period of time, other users might have dropped out, and since they were not there anymore when the study was made, that sample of former Daime members was missing - and their reasons for quitting unknown.
Maybe some of them quit because ayahuasca was causing them trouble or not sitting well with them. And that possibility leaves a gap in the conclusions of the first long term study. That's why now the motivation to join or quit ayahuasca groups, and the evaluation of the experience, is relevant for this research - not because the authors of the research have no idea why people take ayahuasca, but because that information has not been properly included in long term research.
I can assure you that who wrote the note knows ayahuasqueros well.
"The Menu is Not The Meal." - Alan Watts