Genetic Variant Increases Risk of Severe Cocaine Abuse in Whites

A new study has found that nearly one is five white individuals carries a genetic variant that significantly increases his or her odds of severely abusing cocaine. This variant, which is characterized by tiny gene mutations, changes the brain’s response to the rewarding effects of substances such as cocaine. Ohio State University researchers found that carriers of the variant were more than three times more likely to be susceptible to cocaine abuse, which can lead to overdose and death.

The researchers found the mutations in more than 40 percent of autopsy brain samples taken from white people who had died of a cocaine overdose. Of white people who didn’t use drugs, only 19 percent had the mutation. One in five samples from the drug-free group had the variant, compared with one in two to three samples from the cocaine-using white individuals and one in eight African Americans. (The gene variant is less prevalent in African Americans.)

The study found that the mutations affect the way in which the brain reacts to the neurotransmitter dopamine (which is released in the brain after certain activities, including using cocaine). Previous studies have shown that cocaine blocks dopamine transmitters from absorbing dopamine after it is released in the brain, which leads to a feeling of euphoria that the brain eventually associates with cocaine and causes drug cravings.

This is the first study to find a strong connection in brain tissue between the mutations and severe cocaine abuse. However, many questions remain, such as whether the mutations increase the risk of someone trying cocaine in the first place, or whether they strengthen the brain’s drug craving, which leads to severe abuse.

Wolfgang Sadee, senior author of the study and a professor of pharmacology and director of the Program in Pharmacogenomics at Ohio State University, said that their study shows that the gene mutations may impact cocaine abuse, and could help researchers discover new therapies for a range of psychiatric disorders that involve dopamine.

No test currently exists to see whether people are carrying the mutations. Sadee and colleagues are currently examining how these mutations could affect the response of carriers to drugs that act on the gene.

Source: Science Daily, Genetic Trait Could Triple Odds of Whites’ Susceptibility to Heavy Cocaine Abuse, September 22, 2010

Genetic Variant Increases Risk of Severe Cocaine Abuse in Whites is a post from: Drug Addiction Treatment

Source: "Drug Addiction Treatment" via Glen in Google Reader