Hallucinogens as therapeutic agents: Past, Present and Future

Abstract

Hallucinogens have a long history as therapeutic agents. After the synthesis of lysergic acid diethylamide (LSD) in 1938 by Albert Hofmann, the popularity of classical hallucinogens with psychedelic properties increased among scientists, psychiatrists, neurologists, and psychotherapists. Research in the 1950s and 1960s showed great promise for the use of psychedelics in medical research and treatment. Psychedelics are characterized by their mind revealing effects, which are valuable in the treatment of major depressive disorder (MDD) and of stress- and trauma-related mental disorders (PTSD). However, research into thetherapeutic uses of psychedelics became restricted, in part due to their classification as drugs with abuse potential in the mid-1960s. In the past decade, psychedelic research has been reestablished among several groups around the world (Nutt, Erritzoe, and Carhart-Harris, Cell181 (1):24–28, 2020). There is growing anticipation, awareness, and hope for the potential of these substances to become medically approved as psychoactive treatments (Belouin and Henningfield, Neuropharmacology 142:7–19, 2018). In this chapter, we offer a historical overview of psychedelic drugs and their uses and a discussion of chemical and pharmacological properties, mechanisms of action, clinical studies, adverse effects, and psychotherapeutic combination therapies with hallucinogens.