Review links cerebellar signaling with cannabis reward and addiction

Cannabis is the most widely used psychoactive drug, with an estimated 219 million users, according to the United Nations Office on Drugs and Crime (UNODC, 2023). Since 2019, there has been a 32% increase in cannabis use. Although increasing evidence suggests that the cerebellum is involved in addiction-related neural networks, limited research has explored how cannabis exposure impacts cerebellar endocannabinoid (eCB) signaling and how these changes affect reward processing and the development of cannabis use disorder. Signals related to reward can be observed within cerebellar circuitry, particularly in tasks that focus on goal-directed learning. This involves a complex interaction among the cerebellar cortex, basal ganglia, and cerebral cortex, supporting the growing consensus that the cerebellum plays a crucial role in cognitive processing. Moreover, evidence suggests that the cerebellum may integrate both supervised learning and reinforcement learning to improve goal-directed actions. In drug addiction, learned reinforcing properties create powerful motivational triggers for seeking the drug when individuals encounter cues associated with it. Neuroimaging studies in humans indicate that the cerebellum is involved in maintaining memories related to drug use. A detailed understanding of the interplay between cerebellar function, eCB signaling, and reward processing provides a comprehensive framework for understanding the development and persistence of cannabis addiction.