| New Research Study in JAMA Shows Adult
Marijuana Abuse And Dependence Increased During 1990s
In an article appearing in the May 5 issue of the Journal of
the American Medical Association (JAMA), addiction researchers
at the National Institutes of Health compared marijuana use in the
U.S. adult population in 1991-92 and 2001-02. They found that the
number of people reporting use of the drug remained substantially
the same in both time periods, but the prevalence of marijuana abuse
or dependence increased markedly. This new study showed that increases
in the prevalence of abuse or dependence were most notable among
young African-American men and women and young Hispanic men.
This is the first study to assess long-term trends in marijuana
abuse and dependence in the United States using the most up-to-date
classification system-the American Psychiatric Association's Diagnostic
and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).
The researchers from the National Institute on Drug Abuse (NIDA)
and the National Institute on Alcohol Abuse and Alcoholism (NIAAA)
compared trends in marijuana use, abuse, and dependence using the
DSM-IV categories. The DSM defines marijuana abuse as repeated instances
of use under hazardous conditions; repeated, clinically meaningful
impairment in social/occupational/educational functioning; or legal
problems related to marijuana use. Marijuana dependence is defined
as increased tolerance, compulsive use, impaired control, and continued
use despite physical and psychological problems caused or exacerbated
"Marijuana is the most commonly used illegal substance in
the United States, and its use is associated with educational underachievement,
reduced workplace productivity, motor vehicle accidents, and increased
risk of use of other substances," says NIDA Director Dr. Nora
D. Volkow. "This study suggests that we need to develop ways
to monitor the continued rise in marijuana abuse and dependence
and strengthen existing prevention and intervention efforts, particularly
developing and implementing new programs that specifically target
African-American and Hispanic young adults."
Dr. Wilson Compton, Director of the Division of Epidemiology, Services
and Prevention Research at NIDA, Dr. Bridget Grant at NIAAA, and
their colleagues evaluated data from two large, national epidemiologic
surveys conducted 10 years apart the National Longitudinal Alcohol
Epidemiologic Survey (NLAES) and the National Epidemiological Survey
on Alcohol and Related Conditions (NESARC).
A total of 42,862 men and women ages 18 years and older participated
in the 1991-1992 NLAES study, which was conducted by the NIAAA under
the leadership of Dr. Grant. She was also the principal architect
for the 2001-2002 NESARC study, which included 43,093 similarly
aged men and women. Both surveys included the same core questions
to assess marijuana use, abuse, and dependence.
"The value of well-designed and well-executed epidemiologic
studies is that they point to where problems exist and where additional
research and resources must be directed. In addition to the findings
about marijuana, we look forward to learning more about alcohol
disorders indeed, about other mental health disorders, as well from
the same data set," explains Dr. Ting-Kai Li, Director, NIAAA.
"The results of our study show that use of marijuana remained
stable in 2001-2002 compared to 1991-1992; however, there were significant
increases in marijuana abuse or dependence, especially in certain
minority subgroups," says Dr. Compton. "Overall, marijuana
abuse or dependence rose by 22 percent from 1991-1992 to 2001-2002.
This means that there were approximately 800,000 more adults in
the United States with marijuana abuse or dependence in 2001-2002.
Furthermore, marijuana abuse or dependence was more common among
Whites than among minorities in 1991-1992, but by 2001-2002 the
differences in abuse and dependence rates among the different ethnic
groups had narrowed considerably. This change was due to increases
of 224 percent among young African-American men and women aged 18-29,
and 148 percent among young Hispanic men aged 18-29."
The increase in potency of marijuana over the last decade may be
partly responsible for the drug's increased abuse and dependence,
particularly since marijuana use patterns have not changed over
this period. However, no single factor can account entirely for
the increases seen in minority populations, the authors report.
Numerous cultural, psychosocial, economic, and lifestyle factors
likely play roles.
The National Institute on Drug Abuse is a component of the National
Institutes of Health, U.S. Department of Health and Human Services.
NIDA supports more than 85 percent of the world's research on the
health aspects of drug abuse and addiction. The Institute carries
out a large variety of programs to ensure the rapid dissemination
of research information and its implementation in policy and practice.
Fact sheets on the health effects of drugs of abuse and information
on NIDA research and other activities can be found on the NIDA home
page at http://www.drugabuse.gov.
The National Institute on Alcohol Abuse and Alcoholism, a component
of the National Institutes of Health, U.S. Department of Health
and Human Services, conducts and supports approximately 90 percent
of the U.S. research on the causes, consequences, prevention, and
treatment of alcohol abuse, alcoholism, and alcohol problems and
disseminates research findings to science, practitioner, policy
making, and general audiences. Additional alcohol research information
and publications are available at www.niaaa.nih.gov.