Long-term cannabis use and brain structure: an MRI study of a New Zealand longitudinal birth cohort

This study investigated whether cannabis use during adolescent and early adulthood was associated with long-term brain differences into middle-age, using structural T1-weighted, ASL, and diffusion MRI. Compared to non-using controls, users exhibited significantly less grey matter volume in the hippocampus and amygdala (p < 0.05). We observed no significant between-group differences in cerebral blood flow or white matter integrity. While cannabis may relate to long-term brain changes, prospective longitudinal MRI studies may help to elucidate causality.