NEW GROUPS OF POT ABUSERS

CHICAGO - Habitual marijuana use increased among U.S.  adults over the past decade, particularly among young minorities and baby boomers, government figures show.

The prevalence of marijuana abuse or dependency climbed from 1.2 percent of adults in 1991-92 to 1.5 percent in 2001-02, or an estimated 3 million adults 18 and over.

That represents an increase of 800,000 people, according to data from two nationally representative surveys that each queried at least 40,000 adults.

Among adults 18 to 29, the rate of abuse or dependence remained stable among whites but surged by about 220 percent among black men and women, to 4.5 percent of that population, and by almost 150 percent among Latino men, to 4.7 percent.

Among all adults ages 45 to 64, the rate increased by 355 percent, to about 0.4 percent of that population.

The report, published in today's Journal of the American Medical Association ( http://jama.ama-assn.org ), was led by Dr.  Wilson Compton of the National Institute on Drug Abuse, who said the rise in dependence was probably at least partly because of increases in the potency of pot over the past decade.

Also, the figures may indicate that baby boomers "bring their bad habits with them into old age," he said.

The researchers said adults were considered marijuana abusers if repeated use of the drug hurt their ability to function at work, in school or in social situations, or created drug-related legal problems.

Overall use of the drug -- that is, casual use and habitual use -- remained stable at around 4 percent of adults.