Genetic Makeup and Length of Drug Abuse Can Determine Severity of Addiction

A new study from the U.S. Department of Energy’s Brookhaven National Laboratory has shown that drug-dependent individuals with certain genetic makeup have lower gray matter density (and fewer neurons) in areas of the brain that control decision-making, self-control, learning, and memory. This shows that genes can influence the severity of addiction, according to study co-author Nelly Alia-Klein, a medical scientist at Brookhaven.

The study suggests that addicts with low MAOA genotype may need different treatment from those with high MAOA genotype, which could be breakthrough discovery for addiction treatment centers. MAOA is an enzyme that regulates neurotransmitters in the brain, such as serotonin and dopamine. Many drugs release serotonin and dopamine in the brain, controlling mood and behavior.
More research needs to be done before making changes in treatment strategies, but this study is an important first step, and addiction treatment specialists should be informed of these findings.
Previous studies have shown that cocaine addicts have lower gray matter density in parts of the brain that are important for organizing behavior and paying attention, as well as parts of the brain that are associated with learning and memory. The current study found that cocaine addicts with low MAOA had lower gray matter in the orbitofrontal cortex than those with high MAOA or non-addicts.
The current study also found that low gray matter was associated with the number of years of alcohol, cocaine, and cigarette use among the addicts. The longer the abuse, the lower the amount of gray matter in the hippocampus and frontal brain regions. This suggests that being treated for drug addiction may help protect against these brain changes.
In the study, 82 men (40 were addicted to cocaine and 40 were not) were given physical, psychiatric, neurological, and neuropsychological tests, including test of intellectual functioning, and were determined to be healthy and not taking medication.
The researchers took DNA samples of each participant and analyzed them to determine high or low MAOA. They also performed brain scans to determine the density of gray matter in the entire brain. The brain matter volume was compared between the two groups and correlated with genetic makeup and duration of drug abuse.