Microdosing with psychedelics:what do we know?

BACKGROUND: The repeated use of small doses of psychedelics such as psilocybin and lsd over a period of time (microdosing, md) has gained popularity and scientific attention in recent years. Retrospective reports from users suggest clinical potential.<br/> AIM: To answer the question whether md with psychedelics could theoretically provide symptom relief for people with psychiatric disorders. <br/> METHOD: Investigate what the current evidence is about the effects of md with psychedelics on the behavioral level, psychological functioning and mental well-being. A search for relevant articles in PubMed and Medline databases (on January 10, 2020), which resulted in a total of 28 hits. After de-duplication, removal of irrelevant and addition of relevant articles, 23 articles were included.<br/> RESULTS: Most of the knowledge we have so far comes from uncontrolled online questionnaire studies in which users report retrospectively or keep diaries of the effects they experience during md. According to users, it leads to positive effects on mood, concentration, focus and productivity. Negative effects, including physical discomfort and increased fear, also seem to occur. The limited number of experimental studies in healthy people revealed that md has subtle effects on cognitive processes and brain connectivity.<br/> CONCLUSION: The findings of experimental studies in combination with the reports from users give cause for further investigation into the clinical potential of low-dose psychedelics in combating certain symptoms. More placebo-controlled studies are needed to provide clarity for who (age, diagnosis) md can be effective and for which (cognitive, emotional) processes.