Alcoholism in the family tree:
opioids may be one explanation

If your family tree is heavy with alcoholics, you're at high risk to become a problem drinker yourself. According to recent study by Gary Wand and colleagues, this genetic liability may involve reduced activity of opioids, which are natural, opium-like substances produced by the body.

Wand and colleagues compared 26 subjects from families with a strong history of alcoholism to 22 control subjects without a family history of alcoholism. None of the subjects they studied were alcoholics themselves.

The scientists administered the opioid-blocking drug naloxone to the two groups of subjects, using the resulting effect on serum levels of cortisol as an indirect measure of opioid activity in the brain. They report that "individuals from families with a high density of alcohol dependence are more sensitive to naloxone compared with offspring of nonalcohol-dependent parents," an indication that people with a family history of alcoholism have diminished opioid activity.

"This single difference in opioid activity may make people more vulnerable to alcoholism for two reasons," Wand says. "It alters the brain's reward/craving pathway, and it also changes the brain's response to stress." He notes, "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."

"Family history of alcoholism and hypothalamic opioidergic activity," G. S. Wand, D. Mangold, S. El Deiry, M. E. McCaul, and D. Hoover, Archives of General Psychiatry, Vol. 55, No. 12, December 1998, pp. 1114-1119. Address: G. S. Wand, Johns Hopkins University School of Medicine, Baltimore, MD 21205.

"Alcoholics' children: living with a stacked biochemical deck," Medscape Wire, March 30, 1999.