It found that their brain activity was impaired, with the damage continuing into adulthood. The past 20 years has seen major controversy about the long-term effects of marijuana, with experts divided over its long-term effects on teenagers. read more
Much of the research on the long-term cognitive effects of cannabis has focused on heavy users. It's not clear whether there's a safe level of use. Nor is it known whether the brain changes associated with marijuana use are permanent, or if the brain can recover with time. read more