TUESDAY, May 4, 2004 (HealthDayNews) -- While the number of people smoking marijuana hasn't changed much in the past 10 years, the number of people getting hooked on the drug has increased dramatically, especially among minority groups.
That's the conclusion of a new study in the May 5 issue of the Journal of the American Medical Association. And the researchers suspect the increasing potency of marijuana may be to blame for the rise in dependence.
"The quick answer is, we don't know for sure why there's been an increase, but we think it can partly be explained by the potency of marijuana -- marijuana is about twice as potent now as it was 10 years ago," said study author Dr. Wilson Compton, director of the National Institute on Drug Abuse's division of epidemiology, services and prevention research.
"This study reminds us that marijuana is not a harmless substance. It can lead to abuse and dependence just like any other drug," he said.
Compton and his colleagues compared data collected in two large national surveys. The first, the National Longitudinal Alcohol Epidemiologic Survey, was conducted from 1991 to 1992 and included 42,862 participants. The second, the National Epidemiologic Survey on Alcohol and Related Conditions, took place from 2001 through 2002 and included more than 43,000 participants. All of the participants were interviewed in person.
The researchers found the number of people who use marijuana remained largely unchanged during that 10-year period; about 4 percent of the U.S. population uses the drug.
What did change dramatically was the number of marijuana users who were abusing the drug or who had become dependent on it. Marijuana abuse and dependence among users was up nearly 20 percent in 10 years.
"These numbers translate to about 3 million adults dependent on marijuana compared to 2.2 million previously," Compton said.
The greatest increases in abuse and dependence were seen in minority populations. The number of blacks abusing or dependent on marijuana was 21.2 percent in 1991-1992. By 2001-2002 that number was up to 38.6 percent.
Among Hispanics, 23.7 percent reported abuse or dependence during 1991-92; that number jumped to 37.1 percent by 2001-2002.
Among whites, 31.8 percent of marijuana users reported either abusing or dependent on the drug in 1991-1992. In 2001-2002, that number was 34.4 percent.
Dr. Gopal Upadhya is medical director of the Areba Casriel Institute, a private substance-abuse treatment center in New York City. "People have a tendency to think this is a safe drug, but there is no such thing as a safe drug," he said.
Upadhya said it was interesting to see that as the purity of marijuana has increased, the number of addicts has also increased. He likened it to the difference between crack and cocaine.
"One reason crack is difficult for people to get off is because it's purer," he said.
Upadhya said he very rarely sees people seek treatment for marijuana abuse. Often, he said, people start using marijuana and then begin using more and more addictive drugs. The problem, he said, is that people still consider marijuana harmless.
But, according to the National Institute on Drug Abuse, marijuana use can cause memory and learning problems, loss of coordination, a distorted perception of reality, reasoning difficulties, an increased heart rate and an increased risk of cancer. Studies have also associated marijuana use with depression, anxiety and personality disturbances.
Compton said if you continue to use marijuana, even though it's getting you into trouble at work or with family and friends, you may be dependent. Also, if you need more and more of the drug to achieve the same high feeling, you're probably developing a tolerance, which also signals a probable addiction, he said.
More information
To learn more about marijuana and its effects on your health, go to the National Institute on Drug Abuse. Take this quiz from Marijuana Anonymous to learn if you may have a problem with marijuana dependence.
