Role of the endocannabinoid system in the formation and development of depression.

Two types of cannabinoid (CB) receptors have been described in the human body: CB1 and CB2 receptors. CB1 receptor distribution may be related to the cannabinoid functions of memory and cognition regulation as well as motor control. In addition, the endocannabinoid system (ECS) related to CB1 receptors may be involved in human emotion regulation, especially depression occurrence. Indeed, CB1 receptors are all distributed in depression associated neuroanatomical structures and neural circuits. Both animal experiments and clinical studies have demonstrated that impairment of the ECS pathway is present in depression models and patients, and application of both CB1 receptor agonists and anandamide (cannabinoid-like substance) degradation inhibitors produce similar biochemical and behavioral effects as antidepressants. These findings provide a solid basis for understanding the ECS role in the formation and development of depression. Therefore, it can be inferred that the ECS may have an important function in both depression treatment and the effects of antidepressants.