Study Offers Clues To Brain's Protective Mechanisms Against Alcoholism

A new study offers some possible insight into why some high risk people develop alcoholism and others don't:

In this study, researchers compared the number of dopamine D2 receptors in two groups: 16 nonalcoholic individuals with no family history of alcoholism and 15 nonalcoholic individuals who had a positive family history of alcoholism — an alcoholic biological father with early onset of alcoholism and at least two other first or second degree relatives (parent, child, sibling, grandparent, grandchild, cousin, aunt, uncle) with alcoholism. The latter group was at a very high risk of developing alcoholism. The researchers studied high-risk individuals rather than looking at people with drinking disorders because chronic alcohol abuse reduces the number of dopamine receptors, making comparisons difficult. Participants were scanned with positron emission tomography (PET) and were given two radioactive tracers to assess their dopamine D2 receptor levels and brain glucose — a marker of brain function.

The scans demonstrated high levels of dopamine D2 receptors in the brains of participants with a family history of alcoholism, particularly in their frontal regions — 10 percent higher, on average, than in the brains of those with no family history. These areas of the brain — including the caudate and ventral striatum — are involved in emotional reactions to stress and cognitive control of decisions about drinking.