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NIDA Research Report on Marijuana


From the Director

In the 1970s, the baby boom generation was coming of age, and its drug of choice was marijuana. By 1979, more than 60 percent of 12th-graders had tried marijuana at least once in their lives. From this peak, the percentage of 12th-graders who had ever used marijuana decreased for more than a decade, dropping to a low of 33 percent in 1992. However, in 1993, first-time marijuana use by 12th-graders was on the upswing, reaching 50 percent by 1997. Although the percentage of 12th-graders who have experience with marijuana has remained roughly level since then, there is still reason to be concerned.1 In 2002, an estimated 2.6 million Americans used marijuana for the first time. Roughly two-thirds of them were under age 18.2 Furthermore, the marijuana that is available today can be 5 times more potent than the marijuana of the 1970s.3

The use of marijuana can produce adverse physical, mental, emotional, and behavioral changes, and - contrary to popular belief - it can be addictive. Marijuana smoke, like cigarette smoke, can harm the lungs.4,5,6 The use of marijuana can impair short-term memory,7,8 verbal skills,9 and judgment10 and distort perception.11,12 It also may weaken the immune system13,14,15,16 and possibly increase a user's likelihood of developing cancer.14,17 Finally, the increasing use of marijuana by very young teens may have a profoundly negative effect upon their development.9, 18, 19,20

We hope that this research report will help make readers aware of our current knowledge of marijuana abuse and its harmful effects.

Nora D. Volkow, M.D.
National Institute on Drug Abuse


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All materials appearing in the Research Reports Series are in the public domain and may be reproduced without permission from NIDA. Citation of the source is appreciated.

To obtain printed copies of this report, please call or write the National Clearinghouse on Alcohol and Drug Information, P.O. Box 2345, Rockville, MD 20852, 1-800-729-6686. NIDA Research Report - Marijuana Abuse: NIH Publication No. 05-3859, Printed June 2005. This page has been accessed 1761924 times since 11/2/02.


Letter from the Director

What is marijuana?

What is the scope of marijuana use in the United States?

How does marijuana affect the brain?

What are the acute effects of marijuana use?

How does marijuana use affect physical health?

How does marijuana use affect school, work, and social life?

Can marijuana use during pregnancy harm the baby?

Is marijuana use addictive?

What treatments are available for marijuana abusers?

Where can I get further scientific information about marijuana?

Glossary and References


Marijuana Abuse Research Report Cover

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