Cannabis Use and Mental Illness: Understanding Circuit Dysfunction Through Preclinical Models

Area of Science:

• Neuroscience
• Psychiatry
• Pharmacology

Background:

• Patients with serious mental illness (SMI) exhibit higher cannabis use rates and cannabis use disorder (CUD) diagnoses.
• Cannabis psychoactivity is strongly associated with SMI symptoms, with debated therapeutic versus detrimental effects.
• Epidemiological and clinical studies face limitations in establishing causality and examining neurobiology.

Purpose of the Study:

• To review preclinical evidence on shared neurobiological mechanisms between CUD and SMI.
• To consolidate understanding of neural circuit disruptions.
• To generate novel hypotheses and identify therapeutic targets.

Main Methods:

• Review of preclinical studies using rodent models.
• Examination of cannabinoid exposure in healthy and psychiatrically ill rodents (schizophrenia, depression, bipolar disorder).
• Analysis of electrophysiological indices of neural circuit activity.

Main Results:

• Preclinical models demonstrate shared neurobiological underpinnings for CUD and SMI.
• Cannabis exposure impacts neural circuit activity in models of various mental illnesses.
• Evidence suggests specific neural circuits are affected by cannabinoids.

Conclusions:

• Preclinical animal models are crucial for understanding causal effects of cannabis constituents on mental illness.
• A consolidated, neural circuit-based perspective is emerging.
• This understanding can guide the development of novel therapeutic strategies for dual diagnoses.