According to a study published in the American Journal of Public Health, white youth are more likely to abuse hard drugs than blacks of the same age group, shattering a common racial stereotype.

Researchers at Northwestern University interviewed 1,829 young people between the ages of 10 and 18 who were detained at the Cook County Juvenile Temporary Detention Center in Chicago between 1995 and 1998. Researchers then interviewed the participants over a twelve-year period, contacting some of them as many as 9 times during that period. The study found that abuse and dependence on “hard drugs” was “less common among delinquent African American youth than those who are non-Hispanic white.”

Researchers found that the white study participants were 30 times more likely to have used cocaine than the black participants, and the Hispanic youth in the study were 20 times more likely to have used cocaine than the black youth.

“Those findings are striking considering the widely accepted stereotype of African Americans as the most prevalent abusers of ‘hard drugs,'” said Linda A. Teplin, psychiatry professor at Northwestern University Feinberg School of Medicine, and senior author of the study.

“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.” According to Justice Department estimates, one-third of all African Americans will be incarcerated during their lifetimes, compared to one-sixth of all Hispanics, and only one-seventeenth of all whites.

Marijuana was the most commonly used drug among all of the study participants, regardless of race. However, alcohol took over as the most commonly abused drug once the participants reached their late 20s.