A genetic variant increases your risk for cocaine addiction, according to a new study from the Ohio State University. One in five Caucasians has the gene, as well as one in eight African-Americans.

Dr. Wolfgang Sadee and his colleagues studied autopsy reports on the brains of people who died of cocaine overdoses and those who never used drugs at all. Among non-users, 19% had the gene variant, compared to one in two to three of the ones who died of overdoses.

Dr. Sadee is not sure if the gene variant increases a person's risk of trying cocaine in the first place or if it strengthens the craving for the drug.

This study appears in the journal Science Daily.

A recent study from the Mount Sinai School of Medicine found that cocaine can alter the way genes turn on and off in laboratory animals, and the drug can also change the regions of their brains essential for experiencing pleasure.