Abuse and dependence on "hard drugs" (cocaine, hallucinogen or PCP, opiate, amphetamine and sedatives) are less common among delinquent African American youth than those who are non-Hispanic white, according to a new Northwestern Medicine study.

The study offers the first comprehensive picture of drug and alcohol abuse and dependence in delinquent youth after detention. The investigators followed youth up to their late 20s.

During the 12 years after detention, non-Hispanic white youths had 30 times the odds of cocaine use disorder compared with African Americans. Hispanic youths had more than 20 times the odds compared with African Americans.

"Those findings are striking, considering the widely accepted stereotype of African Americans as the most prevalent abusers of 'hard drugs,'" said Linda A. Teplin, senior author of the study and Owen L. Coon Professor of Psychiatry and Behavioral Sciences at Northwestern University Feinberg School of Medicine.

Researchers found that substance use disorders were common and there were substantial sex and racial/ethnic differences. The study, part of the Northwestern Juvenile Project, will be published March 17 in the American Journal of Public Health.

"Our findings add to the growing debate on how the war on drugs has affected African Americans," Teplin said. "We found that African Americans are less likely than other racial/ethnic groups to abuse hard drugs. Yet, African Americans are disproportionately incarcerated for drug crimes."

The 12-year longitudinal study examined 1,829 youth (1,172 males and 657 females, ages 10 to 18 years at baseline) who were detained at the Cook County Juvenile Temporary Detention Center in Chicago between 1995 and 1998. Researchers conducted up to nine follow-up interviews with participants through their 20s.

Among males born in 2001, one in three African Americans and one in six Hispanics will be incarcerated at some point during their lifetimes -- compared with one in 17 Caucasians -- according to a U.S. Department of Justice estimate. "We must address -- as a health disparity -- the disproportionate incarceration of African Americans," Teplin said.

The study also found that 91.3 percent of males and 78.5 percent of females had had a substance use disorder by their late 20s. Males were more likely to have a marijuana and alcohol use disorder than females. Females were more likely to have cocaine, opiate, amphetamine and sedative use disorders than males.

"Unfortunately, substance use disorders were the rule, not the exception," said lead author Leah Welty, associate professor in preventive medicine and of psychiatry and behavioral sciences at Feinberg. "These young adults already face substantial challenges in completing education, establishing careers and building families. Substance abuse further compromises their futures."

Marijuana was the most common substance use disorder during most of young adulthood, the study found. When youth were in their late 20s, however, alcohol abuse and dependence surpassed marijuana.

"Substance abuse is among the most serious health problems in the United States," Welty said. "Rehabilitation and treatment services during incarceration and after would reach a sizeable proportion of people in need and would address health disparities in this highly vulnerable population."