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Signs Of Teen Marijuana Use

Having friends who use marijuana or other substances, such as alcohol and cigarettes, is the No. 1 warning sign that a teenager is likely to smoke marijuana as well, a new study shows.

Researchers looked at what risk factors influence teenagers to start experimenting with marijuana or move from experimental to regular use and found three major risk factors consistently had the biggest impact at all phases of marijuana use among both boys and girls.

At the top of that list is the use of other substances, including alcohol and cigarettes, by the teen or his or her friends. Teens in this category were nearly three times as likely to become regular marijuana users than others.

Two other factors that strongly predicted marijuana use at all stages were delinquency or trouble with the law and school-related problems.

Religious involvement reduced the risk of starting to experiment with marijuana among girls and slightly reduced the risk of transitioning from experimental use to becoming a regular marijuana user.

Risk Factors For Marijuana Use In Teens

In the study, researchers looked at factors associated with marijuana use among a group of more than 13,700 high school students in the U.S. The students ranged in age from 11 to 21 and were surveyed as part of the National Longitudinal Study of Adolescent Health in the USA in 1995 and 1996.

The study showed that more than half of the students who had experimented with marijuana in the first survey continued to use the drug either experimentally or regularly a year later.

Researchers examined the impact of 21 well-established risk factors for adolescent substance use and abuse on five different stages of marijuana use. Three risk factors were the strongest predictors at all stages: the adolescent's own involvement and peer involvement with substances, delinquency, and school problems.

When all three of these risk factors were present, they increased the risk of a student starting to experiment with marijuana by a factor of 20 over the next year.

Researchers say marijuana use during adolescence is associated with a variety of psychological and health problems.

For example, short-term risks associated with marijuana use among teens include traffic accidents and unprotected sex. Long-term use of marijuana can also reduce their chances of graduating from high school and increases the risk of using other substances and psychiatric problems such as depression, anxiety, and suicide.

How To Know If Your Child Is Using Marijuana

According to the National Institute on Drug Abuse, children using marijuana might exhibit the following signs:

  • Seem dizzy and have trouble walking
  • Seem silly and giggly for no reason
  • Have very red, bloodshot eyes
  • Have a hard time remembering things that just happened
When the effects of the drug fade away they may seem very tired. Parents should also look for other symptoms such as withdrawal, depression, fatigue, carelessness with grooming, hostility, and deteriorating relationships with family members and friends.

Sources: van den Bree, M. Archives of General Psychiatry, March 2005; vol 62: pp 311-319. News release, Cardiff University. National Institute on Drug Abuse Web site.
By Jennifer Warner
Reviewed by Brunilda Nazario, MD
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