A new study finds a link between more experiences of discrimination and higher levels of drug use.

“One of the interesting findings of this study is that discrimination is harmful to all groups of individuals, not only racial or ethnic minorities,” researcher Haslyn E.R. Hunte, PhD, said in a news release.

He analyzed data from a study of 3,105 interviews with African American, Hispanic and Caucasian adults living in Chicago. He found 17 percent said they used one or more illicit drugs, and/or misused one or more psychotherapeutic drugs. Marijuana was the most frequently used drug, MedicalXpress reports.

Adults who said they experienced moderate to high levels of everyday discrimination misused on average 1.5 different kinds of drugs more than those who experienced relatively low levels of everyday discrimination, Hunte found. He also found an increase in one lifetime major discrimination event was linked with an increase of misusing 1.3 different drugs on average, regardless of their experiences of everyday discrimination.

“The results suggest that major discrimination like being pulled over unfairly by the police is associated with increased drug use. However, we are unclear as to the exact nature of the relationship: how much discrimination is needed to see a statistically significant association and what is the highest threshold?” Hunte said.

“Mental health and substance abuse providers should consider treating experiences of unfair treatment/discrimination as a risk factor for drug use as they do other experiences of stress, such as the death of a love one,” he added. “They should also not assume that discrimination is only a problem for racial/ethnic minorities.”

The findings are published in the Journal of Urban Health.