Marijuana Abuse Rising Among Adults

Marijuana Use Remains Steady, Dependence on Drug Increasing

Medically Reviewed by Brunilda Nazario, MD on May 04, 2004
From the WebMD Archives

May 4, 2004 -- The number of Americans who use marijuana is holding steady, but a growing number of adults are abusing or dependent on the drug, according to a new study.

Researchers say that trend suggests that the marijuana being sold and used in the U.S. is becoming increasingly potent, which raises the potential risks of drug abuse.

The study shows that marijuana use has remained stable over the last decade with about 4% of adults reporting use of the illegal drug in the past year. But overall rates of marijuana abuse or dependence rose from 1.2% in 1991-1992 to 1.5% in 2001-2002.

"This can be translated into an increase from 2.2 million to 3.0 million, respectively, in terms of population estimates," write Wilson M. Compton, MD, of the National Institute on Drug Abuse, part of the National Institutes of Health, and colleagues.

They define an addiction as a chronic, relapsing disease characterized by compulsive drug-seeking and abuse and by long-lasting chemical changes in the brain.

Although the rates of marijuana dependence and abuse among white young adults remains high, researchers say the most dramatic increases were among young black men and women and young Hispanic men.

Marijuana Abuse Rising

In the study, which appears in the May 5 issue of The Journal of the American Medical Association, researchers looked at changes in marijuana use, abuse, and dependence in the U.S. based on two large national surveys conducted 10 years apart in 1991-1992 and in 2001-2002.

Researchers found about 4% of the respondents reported using marijuana in the past year in both surveys. However, certain groups did show significant increases in marijuana use, such as young black and Hispanic women and middle-age men and women.

The study also showed that marijuana abuse was more common than dependence, and both increased during the last decade. Rates of marijuana abuse rose from 0.9% to 1.1% and dependence increased from 0.3% to 0.4%.

Among those who reported marijuana use in the last year, the rates of abuse or dependence on the drug rose even more significantly, from about 30% in 1991-1992 to nearly 36% in 2001-2002.

Most groups showed increases in marijuana abuse or dependence, but the increases were greatest among young black men and women and young Hispanic men.

Researchers say the results suggest that factors affecting the addiction potential of marijuana are prompting increases in marijuana abuse and dependence. Those factors likely include the increased potency of marijuana being used in the U.S. and rises in marijuana use among youth.

"What is clear is that no single environmental factor can explain the increases in marijuana use disorders observed in this study among certain minority subgroups of the population," write the authors.

"From a broader public health perspective, the results of this study highlight the need to strengthen existing prevention and intervention efforts and to develop and implement widely new programs with the sex, racial/ethnic, and age differentials observed in this study in mind," they conclude.

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SOURCE: Compton, W. The Journal of the American Medical Association, May 5, 2004; vol 291: pp 2114-2121.

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