Caucasian juvenile delinquents are significantly more likely to abuse hard drugs like cocaine and amphetamines than their African-American counterparts, according to new research.

The latest findings go against common African-American stereotypes, according to researchers from Northwestern University.

The study, which looked at rates of substance abuse and dependence on juvenile delinquents after detention, revealed substantial sex and racial differences.

For example, the study revealed that non-Hispanic whites were 30 times more likely and Hispanics 20 times more likely to abuse cocaine compared to their African-American counterparts.

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

"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 latest study involved 12 years of data from 1,829 juvenile delinquents between the ages of 10 and 18 at the beginning of the study. Researchers noted that all participants were detained at the Cook County Juvenile Temporary Detention Center in Chicago between 1995 and 1998.

Study results revealed that 91.3 percent of males and 78.5 percent of females had experienced substance use disorder by their late 20s. While males were significantly more likely to abuse marijuana or alcohol, their female counterparts were significantly more likely to abuse cocaine, opiates, amphetamines and sedatives.

"Unfortunately, substance use disorders were the rule, not the exception," said lead author Leah Welty, according to a university release. "These young adults already face substantial challenges in completing education, establishing careers and building families. Substance abuse further compromises their futures."

"Substance abuse is among the most serious health problems in the United States," Welty added. "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."

Researchers said the latest findings are important because one in three African-American males born in 2001 will be arrested at some point during their lifetimes, compared to one in 17 of their Caucasian counterparts.

"Our findings add to the growing debate on how the war on drugs has affected African Americans," Teplin concluded. "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 findings are published in the American Journal of Public Health.