Dec 1, 1999 Table of Contents

Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit familydoctor.org, the AAFP patient education Web site.

Information from Your Family Doctor

Adverse Effects of Marijuana

Am Fam Physician. 1999 Dec 1;60(9):2593.

See related article on marijuana.

Could I become chemically dependent on marijuana?

Yes. When you're chemically dependent on marijuana, it means you crave it and you need to take more and more to get the same effect. You may have withdrawal symptoms when you stop using it. Because marijuana is a lot stronger than it used to be, you're also more likely to abuse it and become dependent on it today than in the past.

Is marijuana use associated with other drug use?

Yes. Usually people use legal drugs like alcohol or cigarettes before they start using marijuana. Marijuana is the most commonly used illegal substance in the United States. It's often the first illegal drug used and sometimes leads to the use of other illegal drugs.

What are the common side effects of marijuana use?

Some of the common side effects of marijuana are:

  • Trouble remembering things

  • Sleepiness

  • Anxiety

  • Paranoia

  • Altered time perception

Using marijuana for a long time makes some people lose interest in school, work, relationships and other activities. It may cause legal problems and can be dangerous in certain situations, like driving.

How might marijuana affect me physically?

Some of the common physical effects of marijuana include:

  • Tremors

  • Nausea

  • Headache

  • Worsening coordination

  • Breathing problems

  • Increased appetite

  • Reduced blood flow to the brain

  • Changes in the reproductive organs

Like tobacco, marijuana contains many chemicals that can hurt the lungs and cause cancer. One marijuana cigarette can cause more damage to the lungs than many tobacco cigarettes, because marijuana has more tar in it and is usually smoked without filters. Unpleasant side effects from marijuana occur in about 40 to 60 percent of people who use marijuana.


This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at http://familydoctor.org.

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.

Copyright © 1999 by the American Academy of Family Physicians.
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