Prevalence of marijuana use disorders in the United States: 1991-1992 and 2001-2002.

CONTEXT Among illicit substance use disorders, marijuana use disorders are the most prevalent in the population. Yet, information about the prevalence of current Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) marijuana use disorders and how prevalence has changed is lacking. OBJECTIVE To examine changes in the prevalence of marijuana use, abuse, and dependence in the United States between 1991-1992 and 2001-2002. DESIGN, SETTING, AND PARTICIPANTS Face-to-face interviews were conducted in 2 large national surveys conducted 10 years apart: the 1991-1992 National Longitudinal Alcohol Epidemiologic Survey ([NLAES] n = 42,862) and the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions ([NESARC] n = 43,093). MAIN OUTCOME MEASURES Rates of past year marijuana use, abuse, and dependence. RESULTS Among the adult US population, the prevalence of marijuana use remained stable at about 4.0% over the past decade. In contrast, the prevalence of DSM-IV marijuana abuse or dependence significantly (P =.01) increased between 1991-1992 (1.2%) and 2001-2002 (1.5%), with the greatest increases observed among young black men and women (P<.001) and young Hispanic men (P =.006). Further, marijuana use disorders among marijuana users significantly increased (P =.002) in the absence of increased frequency and quantity of marijuana use, suggesting that the concomitant increase in potency of delta-9-tetrahydrocannabinol (Delta9-THC) may have contributed to the rising rates. CONCLUSIONS Despite the stability in the overall prevalence of marijuana use, more adults in the United States had a marijuana use disorder in 2001-2002 than in 1991-1992. Increases in the prevalence of marijuana use disorders were most notable among young black men and women and young Hispanic men. Although rates of marijuana abuse and dependence did not increase among young white men and women, their rates have remained high. The results of this study underscore the need to develop and implement new prevention and intervention programs targeted at youth, particularly minority youth.