Primum Non Nocere: The Onus to Characterize the Potential Harms of Psychedelic Treatment.

The last few years have seen exponential growth in interest, investment, advocacy, and research into psychedelics as therapeutics. This reflects an optimism about the potential promise of psychedelics as therapeutics. As with all therapeutic interventions, research is needed not only into their benefits but also potential risks. Indeed, when substances with therapeutic potential are scrutinized over time, especially in broad populations with psychiatric and medical comorbidities typically excluded from clinical trials, and applied in less well-regulated or controlled settings, a greater understanding of the cautions emerges. Here, we review the literature on the known and potential harms, including enduring perceptual disturbances; triggering or enhancing the risk for onset of mania or psychosis; overuse, misuse, and dependence; challenging experiences or "bad trips"; risks associated with increased neuroplastic potential; and acute and cumulative cardiovascular effects. Each of these issues is addressed in this review, along with the call for continued research, including recommendations for further research and monitoring.