Children of alcoholics have an altered brain chemistry that appears to make them more likely to become alcoholics themselves, according to a recent study by Johns Hopkins scientists.
Using a drug-based technique that highlights differences in natural opioid activity in the brain, the researchers found such activity was significantly less in the young adults they studied from strongly alcoholic families.
"This is the first evidence that the brains of the non-alcoholic children of alcoholics differ in the activity of specific brain circuits most scientists link with alcoholism, and that those differences exist before the onset of heavy drinking," says neuroendocrinologist Gary S. Wand, M.D., who led a team of Hopkins researchers. The study was reported in the December Annals of General Psychiatry.
"This single difference in opioid activity may make people more vulnerable to alcoholism for two reasons," says Wand: "It alters the brain's reward/craving pathway and it also changes the brain's response to stress." Scientists have long suggested the reward pathway -- well-endowed with opioid receptors -- is key in alcoholism. "And we know that stress is involved in many kinds of drug-seeking behavior," he adds.
The difference could serve as a marker to predict family members at increased risk of alcoholism, Wand says.
The researchers compared 26 young adults with a strong family history of chronic drinking -- all had at least fathers who were alcoholics -- with 22 counterparts who had no such history. The scientists indirectly measured opioid activity in the brain by artificially blocking opioids in both groups with a drug called naloxone and then measuring the "downstream" effect on blood levels of cortisol, a hormone the body releases in response to stress. The differences in cortisol and, hence, in opioid activity between the two groups were significant.