This Viewpoint discusses the potential promise of the therapeutic use of psychedelics for mental illness and substance use disorders, acknowledging many open research questions and unique challenges with these substances.
Chronic cannabis (marijuana, hashish) smoking can result in dependence. Rodent studies show reversible downregulation of brain cannabinoid CB1 (cannabinoid receptor type 1) receptors after chronic exposure to cannabis. However, whether downregulation occurs in humans who chronically smoke cannabis is unknown. Here we show, using positron emission tomography imaging, reversible and regionally...