White Matter and Marijuana

Did you know that the age at which a brain is exposed regularly to marijuana may result in different effects to white matter? Typically, marijuana use begins during adolescence and early adulthood. This is a particularly dangerous age because the brain is still developing and cannabis receptors are still abundant in white-matter pathways. Researchers at Oxford University found impaired axonal pathways in the hippocampus and portions of the bridges (e.g., corpus callosum, commissure) that connect the two hemispheres in the brain of regular cannabis users. The amount of impairment to these brain areas was directly associated with the age at which the individual began regular use of marijuana. Study results suggest that long-term cannabis use is hazardous particularly to white matter in the developing brain of adolescents and young adults. Delaying the age at which regular use begins may minimize the severity of microstructural impairment. White matter alteration has been linked with several health concerns including cognitive impairment; vulnerability to psychosis, depression, and anxiety disorders; and clinical outcomes in schizophrenia.