Teenagers who smoke marijuana daily may be damaging their brains and making themselves more prone to depression and anxiety as adults, according to a new study out of McGill University.
The researchers at the University found that when adolescent and adult lab rats were exposed to the active ingredient in marijuana for 20 days, only the adolescent rats were adversely affected.
Changes observed in the rats included a decrease in a substance in the brain called serotonin, which is believed to play a role in depression. Increases in another substance called norepinephrine, which has been associated with anxiety, were also noted.
Although the study was carried out on rats, study author Gabriella Gobbi said the results could be extrapolated to humans.
The results suggest, according to Gobbi, that because the adolescent brain is still developing, it may be particularly vulnerable to chronic drug use.
Earlier research done by Gobbi found that marijuana can act as an antidepressant, but only in the short-term. If used long-term, the opposite effect occurs.
The new study appears in the latest issue of Neurobiology of Disease.