Understanding subjective experience in psychedelic-assisted psychotherapy: The need for phenomenology.

Psychedelic-assisted psychotherapy is being investigated as a treatment for a range of psychiatric illnesses. Current research suggests that the kinds of subjective experiences induced by psychedelic compounds play key roles in producing therapeutic outcomes. To date, most knowledge of therapeutic psychedelic experiences are derived from psychometric assessments with scales such as the Mystical Experience Questionnaire. While these approaches are insightful, more nuanced and detailed descriptions of psychedelic-induced changes to subjective experience are required. Drawing on recent advancements in qualitative methods arising from the interdisciplinary field of phenomenological psychopathology, we propose a systematic and comprehensive investigation into how psychedelic-assisted psychotherapy alters subjective experience. This research programme aims to characterise the nature of therapeutic psychedelic experiences by drawing on concepts from philosophical phenomenology. Such characterisations should, moreover, contribute to our understanding of the mechanisms of psychedelic therapy, the role of integration therapy, and related philosophical debates.