Teen pot use nothing to scoff at


Teen marijuana use is a big deal. Teenagers are especially vulnerable to the effects of marijuana. About 60 percent of new users every year are under the age of 18, and two-thirds of adolescent substance treatment admissions are for marijuana.

Since the explosion of medical marijuana use in Colorado, my adolescent substance treatment program is seeing more referrals, and teens are reporting more severe marijuana dependence, easier access to marijuana and more favorable opinions about marijuana.

Diversion of medical marijuana to youth is very common, and youth are specifically targeted by medical marijuana marketing.

All these changes make treatment more difficult because teens are less likely to see marijuana use as harmful, and they relapse into drug use more easily because of the increased presence of marijuana and marijuana advertisements.

Adolescence is an important time of brain development. Because their brains are not yet fully developed, teens are more likely to become addicted to marijuana than are adults.

Of adolescent first-time users, 17 percent go on to develop marijuana abuse or dependence. This compares to 4 percent of people who first use marijuana as adults.

And yes, marijuana can produce both psychological and physical dependence. There is no longer debate in scientific circles about whether marijuana is both physically and psychologically addictive.

New findings show that marijuana may affect brain development permanently. Adolescence is an important period of brain development, and the brain receptor to which marijuana binds plays a crucial role in this process. This is the reason why marijuana is thought to be toxic to brain development.

For example, adolescents who use marijuana before the age of 18, compared to those who have never used before that age, have up to a three-fold increased risk of developing permanent psychosis as adults.

This risk is dose-dependent, meaning that the more marijuana is used, the greater the risk of developing psychotic symptoms. This relationship between teen marijuana use and psychosis has been replicated in at least seven large studies that control for a wide variety of environmental and biological factors.

Adolescents who use marijuana before the age of 17, compared to those who use the drug after that age, also have decreased verbal intelligence, decreased verbal fluency, decreased word recall, decreased visual scanning ability, decreased reaction time and decreased whole brain volume as adults.

This finding mirrors animal research, which shows that adolescent exposure to tetrahydrocannabinol, the main active ingredient of marijuana, causes permanent deficits in attention, motivation and memory.

Finally, adolescent marijuana use primes the brain for developing other substance use disorders.

This means that using marijuana as an adolescent may change the brain to respond more favorably to other addictive substances.

Multiple studies show that teenagers who use marijuana are two to three times more likely to use other illicit substances than are their peers who don't use marijuana.

While some of this increased risk may be due to social reasons (for example, teens who know where to buy marijuana are more likely to know where to buy other substances), studies show that a significant proportion of this increased risk of moving on to other substances is due to biological reasons.

Dr. Christian Thurstone is a board-certified child psychiatrist and addiction psychiatrist. He is an assistant professor of psychiatry at the University of Colorado Denver and a nationally recognized researcher in the field of adolescent substance treatment. For information on local recovery support services, go to Trilogy Recovery Community's website at www.trilogyrecovery.org or call 509-876-4525.


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