High-Potency Marijuana May Damage Nerve Fibers in Brain, Study Suggests

A new study suggests smoking high-potency marijuana may cause damage to nerve fibers responsible for communication between the brain’s two hemispheres.

The study included MRI scans of 99 people, including some who were diagnosed with psychosis, HealthDay reports. The researchers found an association between frequent use of high-potency marijuana and damage to the corpus callosum, which is responsible for communication between the brain’s left and right hemispheres.

The corpus callosum is especially rich in cannabinoid receptors. THC, the psychoactive ingredient in marijuana, acts on these receptors.

Today’s high-potency marijuana has been shown to contain higher proportions of THC compared with a decade ago. Scientists have known that the use of marijuana with higher THC content has been associated with greater risk and earlier onset of psychosis, the researchers noted. This study is the first to examine the effect of marijuana potency on brain structure, according to a news release from Kings’s College London.

Frequent use of high-potency marijuana significantly affected the structure of the corpus callosum in patients with or without psychosis, the researchers report in Psychological Medicine. The more high-potency marijuana a person smoked, the greater the damage.

“There is an urgent need to educate health professionals, the public and policymakers about the risks involved with cannabis use,” said senior researcher Dr. Paola Dazzan of the Institute of Psychiatry, Psychology & Neuroscience at King’s College London. “As we have suggested previously, when assessing cannabis use it is extremely important to gather information on how often and what type of cannabis is being used. These details can help quantify the risk of mental health problems and increase awareness on the type of damage these substances can do to the brain.’