Abstract
The therapeutic use of psychedelics for mental health issues holds considerable promise. However, systematic assessment of adverse events associated with these substances has received relatively little attention. Here, we discuss several considerations concerning the assessment of adverse events in psychedelic-assisted therapies. We discuss the preference for using the term "adverse effects" over "side effects", as well as the ongoing debate regarding which substances are classified as psychedelic. We also provide recommendations on when and how to assess adverse effects, for example the importance to study them in any kind of therapy involving psychedelics, and using comprehensive monitoring of a wide range of physical parameters in combination with behavioral outcomes and the individual's experience, at baseline and throughout the study. Also, sex-specific differences should be considered. Furthermore, we highlight several significant studies that have addressed these aspects. In summary, psychedelics offer great promise as a potential treatment (add-on) option in psychiatry, but more rigorous assessment of adverse effects is needed to promote safe use and implementation in clinical practice.