Chronic Cannabis Use and Axonal Fiber Connectivity

Abstract

Evidence that long-term cannabis use may be hazardous to white matter in the developing brain has been accumulating, with early onset use in particular thought to impair structural morphology and integrity, during the critical neurodevelopment occurring in adolescence. We found specific localized axonal connectivity disturbances in adult long-term heavy cannabis users, with 84-88% reductions in streamlines in the fimbria of the hippocampus, and commissural fibers extending to the precuneus. White matter integrity within these fiber bundles was associated with the age of onset of cannabis use. The endocannabinoid system is critically involved in axonal growth in the developing brain; mechanis..