PET Molecular Imaging of the Endocannabinoid System in Psychiatric Disorders.

Psychiatric disorders have emerged as significant contributors to the global burden of disease in recent decades. The endocannabinoid system (ECS) influences a range of physiological and pathophysiological processes, including nociception, cognition, appetite, memory, and behavior, serving as a crucial mediator in psychiatric disorders. Imaging the ECS provides valuable insights into the pathophysiological mechanisms underlying psychiatric disorders and enhances clinical management strategies. As an advanced noninvasive molecular imaging modality, positron emission tomography (PET) enables the in vivo exploration of biological processes at the cellular and molecular levels. Recent advancements have led to the development of numerous PET tracers that target various components of the ECS, offering opportunities to visualize, characterize, and quantify ECS activity in psychiatric disorders in vivo. In this review, we summarize the existing PET tracers for ECS imaging and discuss their applications in diverse psychiatric conditions, including cannabis use disorder, alcohol use disorder, post-traumatic stress disorder, schizophrenia, and eating disorders.