As the Trudeau government considers how quickly to move on its promise to legalize marijuana, researchers at Western University are telling the government to make sure pot stays out of the hands of teenagers.
They warn pot's active ingredient has "significant, long-term impacts" on the adolescent brain.
A study conducted by a team at the Sculich School of Medicine and Dentistry and Western's Addiction Research Group found younger rats that were exposed to delta-9-tetrahydrocannabinol (THC) displayed behavioural, neuronal, and molecular changes identical to conditions like schizophrenia.
By contrast, adults rats exposed to THC showed no such changes.
The researchers found the adolescent rodents exposed to THC were socially withdrawn and more anxious. They also had cognitive disorganization and abnormal levels of dopamine. All of these symptoms are found in populations of people with schizophrenia. The changes continued into the rodents' adulthood, long after the initial THC exposure.
Adult rodents did not show these symptoms, although the researchers did observe in them decreased social cognition and memory.
Researcher Steven Laviolette, PhD, professor in the departments of Anatomy and Cell Biology, and Psychiatry says there are clear implications for what his team found.
“Adolescence is a critical period of brain development and the adolescent brain is particularly vulnerable,” says Laviolette. “Health policy makers need to ensure that marijuana, especially marijuana strains with high THC levels, stays out of the hands of teenagers. In contrast, our findings suggest that adult use of marijuana does not pose substantial risk.”
The study was published online in the January issue of Cerebral Cortex