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Alcohol affects the teen brain differently because of the critical brain development occurring from ages 12 through 20, often until age 25.
A survey of a nationally representative sample of U.S. teenagers suggests that most cases of alcohol and drug abuse have their initial onset at this important period of development, according to a report published in the April issue of Archives of General Psychiatry, a JAMA Network publication.

Alcohol and drugs use patterns in adolescence are increasingly seen as indicators of later substance abuse, the authors write in their study background.

Joel Swendsen, Ph.D., of the University of Bordeaux, France, and colleagues examined the prevalence, age at onset and sociodemographic factors related to alcohol and illicit drug use and abuse by U.S. adolescents. Their cross-sectional survey included a nationally representative sample of 10,123 adolescents ages 13 to 18 years.

Their study results indicate that by late adolescence, 78.2 percent of teenagers reported having consumed alcohol; 47.1 percent having reached regular drinking levels of at least 12 drinks within a year; and 15.1 percent having met the criteria for lifetime abuse. The opportunity to use illicit drugs was reported by 81.4 percent of the oldest adolescents, drug use by 42.5 percent and drug abuse by 16.4 percent.

"Because the early onset of substance use is a significant predictor of substance use behavior and disorders in a lifespan, the public health implications of the current findings are far reaching," the authors note.

The median age at onset was 14 years old for regular alcohol use or abuse with or without dependence; 14 years old for drug abuse with dependence; and 15 years old for drug abuse without dependence.

The probability of each stage of alcohol and drug use increased with age, but the rates were almost always lowest for black and other racial/ethnic groups compared with white or Hispanic adolescents.

The researchers also note that using the term "lifetime" to describe the prevalence of substance use disorders in teenagers does not necessarily indicate the persistence of these disorders in the long term because adolescents may "mature out" of harmful substance use as they become adults.

"The prevention of both alcohol and illicit drug abuse requires strategies that target early adolescence and take into account the highly differential influence that population-based factors may exert by stage of substance use," the authors conclude.

Journal Reference:
J. Swendsen, M. Burstein, B. Case, K. P. Conway, L. Dierker, J. He, K. R. Merikangas. Use and Abuse of Alcohol and Illicit Drugs in US Adolescents: Results of the National Comorbidity Survey-Adolescent Supplement. Archives of General Psychiatry, 2012; 69 (4): 390 DOI: 10.1001/archgenpsychiatry.2011.1503