Classic and non‐classic psychedelics for substance use disorder: A review of their historic, past and current research

Substance use disorder (SUD) is a global public health concern that affects millions of people worldwide. Considering current research, addiction has been noted as the last stage of a chronic disease that may impair brain reward circuit responses and affects personal and social life. Treatments for SUD face challenges including availability and limited pharmacological response, often resulting in low retention of patients. A growing number of studies from the ‘psychedelic renaissance’ have highlighted the therapeutic potential of psychedelics for several psychiatric disorders, including SUD. In this non-systematic review we discuss past and current clinical and observational studies with classic (LSD, DMT, psilocybin and mescaline) and non-classic (ibogaine, ketamine, MDMA, salvinorin A and THC) psychedelics for the treatment of SUD published until December 2021. Although results are still inconclusive for LSD, DMT, mescaline, MDMA and Salvinorin A, in general, the literature presents moderate evidence on the controlled use of psilocybin and ketamine for Alcohol Use Disorder, ketamine for management of opiate and alcohol withdrawal, and THC preparations for reducing withdrawal symptoms in Cannabis and possibly in Opioid Use Disorder. Importantly, studies suggest that psychedelics should be more effective when employed as an adjunct therapy. Extensive research is warranted to further elucidate the role of psychedelics in the treatment of SUD.