Acute psychedelic experience intensity 'main predictive factor' for treatment response

A systematic review has outlined clinical and biological predictors of psychedelic response in treating psychiatric and addictive disorders.

The main predicting factor of response was intensity of the acute psychedelic experience, researchers reported in Journal of Psychiatric Research.

“Despite [prior] very promising results, not all patients respond to psychedelic treatments,” Bruno Romeo, of the department of psychiatry and addictology at Paul Brousse Hospital in France, and colleagues wrote. “For example, 43% of [treatment-resistant depression] had not achieved any response by day 7 to ayahuasca and 33% of smokers relapse during the 12-month follow-up after psilocybin treatment. Therefore, it seems important to better identify the population of patients susceptible to respond to psychedelics.”

The investigators searched four databases between January 1990 and May 2020 for all studies that investigated which factors predicted psychedelic response regardless of psychiatric or addictive disorders. They included 20 studies in qualitative synthesis. Included studies investigated addictive disorder, treatment-resistant depression (TRD) and obsessive-compulsive disorder, as well as depressive and anxiety symptoms among individuals with life-threatening cancer.

Results showed intensity of the acute psychedelic experience was the main predictive factor of response to psychedelics in all indications. The researchers found this factor for alcohol and tobacco use disorders, TRD and anxiety and depressive symptoms in individuals with life-threatening cancer, but not for OCD.

“Further clinical studies are needed to clarify the importance of predictive factors, firstly, in order to confirm these results and, secondly, in order to expand research towards other fields of investigation, such as the impact of different psychotherapeutic methods on psychedelic efficacy,” Romeo and colleagues wrote.