Abstract

The return of fear in patients with PTSD and anxiety who showed a marked reduction in fear during exposure therapy is a major challenge in the treatment of these disorders. One mechanism contributing to the elevated levels of fear and anxiety in patients is the deficiency of fear extinction recall. Preclinical and clinical trials showed that psychedelic-assisted psychotherapy can achieve a more long-lasting fear reduction than psychotherapy alone. Thus, it is hypothesized that improvement of fear extinction might be one important therapeutic mechanism of psychedelics.

This talk will summarize the available evidence from animal and human studies with regard to the effects of psychedelics on the recall of fear extinction. The results suggest that an enhancement of fear extinction recall through MDMA, Ayahuasca, or DMT in rodents is possible. However, the evidence is limited and, in some cases, contradictory. Relevant aspects for future studies will pointed out, such as the importance of performing a delayed fear extinction recall test to evaluate whether long-term fear reduction was effectively achieved.