How does cannabis affect the prefrontal cortex and executive function?

The prefrontal cortex (PFC) — responsible for planning, decision-making, impulse control, and working memory — is highly sensitive to cannabinoid modulation. CB1 receptors are densely expressed on PFC pyramidal neurons and interneurons. Acute THC disrupts PFC function by impairing dopamine-glutamate balance, reducing working memory capacity, slowing processing speed, and impairing inhibitory control. fMRI studies show altered PFC activation patterns during cognitive tasks after acute THC. In adolescents, whose PFC is still developing until age 25, chronic cannabis exposure is associated with structural changes (reduced gray matter volume, altered white matter integrity) and persistent cognitive deficits that may not fully resolve. In adults, acute PFC impairment resolves within hours; chronic effects are more modest and largely reversible with abstinence. The adolescent brain is substantially more vulnerable.