Healthy individuals with a family history of alcohol use disorder (AUD) release more dopamine in the brain’s primary reward center in the expectation of alcohol than those who are actually diagnosed with the disorder, or healthy people without any family history of AUD, according to a new study published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.
“This exaggerated reward center stimulation by expectation of alcohol may put the [individuals with family history] at greater risk of alcohol use disorder, and could be a risk factor in itself,” said first author Lawrence Kegeles, MD, PhD, of Columbia University.
For the study, the researchers evaluated 15 participants diagnosed with AUD, 34 healthy participants with no family history of AUD, and 16 healthy participants with a family history of the disorder (referred to as the family-history positive, or FHP, group).
The researchers used PET (positron-emission tomography) brain scanning to measure the amount of dopamine released in regions of the brain associated with reward and addiction. The participants received the brain scans after being given either an alcohol drink — a cocktail of vodka, tonic, and cranberry — or a placebo drink without the vodka.
While the participants weren’t told the order in which they would receive the drinks, if they received the placebo drink first they were cued into expecting the alcohol drink next.
All three groups had similar dopamine release-levels in response to the drinks that contained actual alcohol, suggesting that alcohol-induced dopamine release is a normal response in those with AUD.
However, “we found that the FHP participants had a much more pronounced response to the placebo drink than the other groups, indicating that expectation of alcohol caused the FHP group to release more reward center dopamine,” said Kegeles.
Researchers believe that it is the release of dopamine into this primary reward center that reinforces alcohol consumption and possibly contributes to the risk of AUD.
“This research finding exemplifies how advances in imaging brain chemistry using PET scanning can provide new insights into how differences in brain function in people with a family history of alcoholism can explain their own potential for addiction,” said Cameron Carter, MD, and editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.
The current study did not follow the subjects to see whether the increased dopamine response could actually predict development of AUD at a higher rate, so more research will be needed to determine if this abnormality does, in fact, increase risk for alcohol use disorder.