New insights into the clinical and nonclinical effects of psychedelic substances: an integrative review

After decades of stagnancy, research on psychedelic substances (such as LSD, psilocybin or DMT) has experienced a renaissance over the last 10 years, with various major research programs being conducted across Europe and the United States. This research primarily investigates the potential of psychedelics in the treatment of mental health disorders, their short and long term effects on recreational users, and the neurological and cognitive processes responsible for their effects. The present review provides a concise summary of the most recent insights gained from this research. We briefly outline the history of psychedelic research, the objective and subjective effects caused by these substances, the prevalence and socio-psychological correlates of their use, as well as their potential for harm. Subsequently, we review empirical research on the beneficial effects of psychedelics in clinical samples, focusing on their efficacy in the treatment of major depression, anxiety, and substance use disorders, and discuss research on the proposed neural and cognitive mechanisms behind these effects. We then review research on their effects on healthy subjects, focusing on psychological wellbeing as well as changes in personality, nature relatedness, and creativity. Finally, we review empirical evidence regarding long-term effects of single experiences with psychedelics, and conclude with a brief summary and outlook.