Commentary: Marijuana Use and Adolescents: What Clinicians Need to Know

As marijuana use among teenagers increases and its perceived danger among this age group decreases, clinicians need to know the latest science about the harmful effects of the drug on the adolescent brain, according to a researcher at the University of Colorado, Denver.

Paula Riggs, PhD, Professor of Psychiatry, notes the most recent Monitoring the Future Survey shows a significant increase in marijuana use, including daily marijuana use among U. S. high school students and a decrease in perceived risk of use. “There are a number of indicators, including the increasing number of states that have passed ‘medical marijuana’ legislation, and that society as a whole tends to view marijuana as a relatively benign, recreational drug. However, scientific research does not support this.”

A growing body of research shows that adolescent marijuana use can be detrimental to the brain development and may produce long-lasting neurocognitive deficits and increased risk of mental health problems including psychosis, said Dr. Riggs, who spoke about this topic at the recent California Society of Addiction Medicine meeting.

Marijuana is the most commonly used illicit drug in the United States. Although some have questioned whether marijuana is an addictive drug, scientific research shows that one in 10 people overall, and one in six adolescents, who use marijuana develop dependence or addiction, Dr. Riggs says. Research shows that marijuana can cause structural damage, neuronal loss and impair brain function on a number of levels, from basic motor coordination to more complex tasks, such as the ability to plan, organize, solve problems, remember, make decisions and control behavior and emotions.

Dr. Riggs also cited recent studies indicating that adolescents may be more vulnerable to addiction, in part due to rapid brain development. “Emerging research suggests that individuals who start using marijuana during their teenage years may have longer-lasting cognitive impairments in executive functioning than those who start later,” she says. “Animal studies also suggest that exposure to marijuana during adolescence compared to adulthood may increase the vulnerability or risk of developing addiction to other substances of abuse such as cocaine and methamphetamine.”

She adds, “It is important for pediatricians, psychiatrists and other mental health clinicians to be aware of current research because they are on the front line to identify teens when they first start to experiment. They need to be able to effectively screen adolescents for marijuana use, and be armed with the scientific facts to educate teens and families about associated risks.”