The Role of Genes in Drug Addiction

Are genetic factors related to drug addiction? Current research shows that, indeed, genes play a major part in addiction: at least 50% of a person’s susceptibility to addiction can be associated with genetic factors.

At last year’s congressional hearing organized by APA’s Science Government Relations Office, presenters outlined new research about the genetic basis for drug addiction and suggested ways to incorporate research findings into treatment.

According to Alexandra Shields, director of the Harvard University/Massachusetts General Hospital Center on Genomics, Vulnerable Populations and Health Disparities, researchers must first overcome public distrust and misunderstanding about genetic testing. This means that the public and physicians must have a deeper understanding regarding the interactions between addiction and genetics.

A national survey reveals that only 5% of primary-care physicians are confident about their ability in interpreting genetic tests, and only about 4% would feel positive suggesting treatments based on genetics.

Nora Volkow, director of the National Institute on Drug Abuse said that physicians have very good reasons to pay close attention to the effects advances in genetics will likely have on their capability to treat patients. "Understanding the complex interactions between the factors involved in drug abuse and addiction is critical to their effective prevention and treatment, Volkow added.

With the emergence of latest data, physicians might soon include genetic testing in their practice, enabling them to match specialized treatments to individuals. For instance, the number of some type of dopamine receptor (D2) might be used in the future to predict whether a person will become addicted to cocaine, heroin, and alcohol.

Brain imaging implies that those with smaller number of D2 receptors have higher chances of becoming addicted than people with more D2 receptors. How many of D2 receptors people have is partly genetically determined.

Certainly environmental factors also play an important role, so tendency is not destiny. First an individual has to use drugs, and then he/she must repeatedly use them. Genetic susceptibility at that point helps determine who ends up addicted.