Genetics may make whites crave cocaine.

• Position: Drug Abuse

Nearly one in five white individuals could carry a genetic variant that substantially increases the odds of being susceptible to severe cocaine abuse, according to research from the University of Miami School of Medicine, Coral Gables.

This genetic variant, characterized by one or both of two tiny gene mutations, alters the brain's response to specific chemical signals. In the study, the variant was associated with a more than threefold increase in the odds that carriers will be susceptible to severe cocaine abuse leading to fatal overdosing, compared to noncarriers.

Among whites, one or both mutations was found in mere than 40% of autopsy brain samples taken from people who had abused compared to 19% of samples from people who lived drug-free. Overall, one in five samples from whites in the control group and one in two to three samples in the cocaine overdose group contained the genetic variant, compared to one in eight African-Americans.

The mutations--either alone or in combination--affect how dopamine modulates brain activity. Dopamine, a neurotransmitter, is a chemical messenger vim to the regular function of the central nervous system. Previous research has established that cocaine blocks dopamine transporters from absorbing dopamine...