Marijuana use and adolescence don’t mix

Teenagers’ rapidly developing brains put them at high risk of harm from marijuana use, a review of the drug’s adverse effects emphasizes.

Scientists at the National Institute on Drug Abuse (NIDA), who wrote the review, note that active brain development during adolescence leaves the brain especially vulnerable to exposure to environmental chemicals such as tetrahydrocannabinol, the active ingredient in marijuana. This may help explain why teenagers are particularly prone to suffer adverse effects from regular and early use of marijuana. The effects include greater potential for addiction than adults; impaired critical thinking and memory that persists for days after use; poor school performance; increased risk of dropping out; and lower achievement later in life.

Teenagers who use marijuana are 2 to 4 times more likely as adults to develop symptoms of dependence within 2 years of starting the drug.

A long-term study in 2012 showed that regular marijuana use in early adolescence led to neuropsychologic decline, including lowered IQ and cognitive impairment. The effects persisted into adulthood and quitting the drug didn’t fully reverse them. Adults who smoked marijuana regularly as teenagers have fewer neural connections in important areas of the brain that involve functions such as learning and memory, executive functions (including control of inhibitions), and processing of habits and routines.

The NIDA-supported 2013 Monitoring the Future Survey found that 6.5% of high school seniors report using marijuana daily or almost every day; 60% aren’t aware of the drug’s adverse effects. This gives pediatricians an important role to play in educating families and teenagers about marijuana’s harms.

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