The Psychological Change Processes in the Antidepressant Effects of Psychedelic-Assisted Psychotherapy: A Mixed Methods Investigation

Whilst research into psychedelic-assisted psychotherapy has produced promising results in the treatment of depression, further investigations are needed into how it works to produce antidepressant effect. The current thesis involved a multi-faceted scoping investigation of possible psychological mechanisms of action of psychedelic-assisted psychotherapy for depression, and includes three individual studies: a systematic review, Delphi study, and qualitative interviews with participants in a clinical trial of psilocybin-assisted psychotherapy for treatment resistent depression. Results from all three studies were synthesised to produce a proposed framework of psychological mechanisms of action in psychedelic-assisted psychotherapy to support future research in the field.