Personality vulnerabilities and adverse event reporting in phase 1 clinical studies

Phase 1 clinical trials involve rigorous safety monitoring to identify any adverse effects of investigational treatments. There is growing evidence that healthy volunteers recruited in these studies may differ with respect to personality traits from the general population. This, in turn, may have a significant impact on the reporting of adverse events, particularly in trials investigating psychoactive treatments, including the psychedelic substances.

This analysis stems from our combined experience as investigators in phase 1 clinical trials and conveys an experiential understanding of the impact of psychological heterogeneity on study participation, reporting of adverse events and study outcomes.

Participant variability due to psychological characteristics is regularly overlooked in phase 1 clinical trials and may significantly impact on reporting of the adverse events. In our opinion, healthy volunteers who present for these studies should not only be defined by the absence of past or current medical and psychiatric illness but also characterised by their psychological attributes.