EFFECT OF DIAZEPAM ON PLASMA GAMMA-AMINOBUTYRIC-ACID IN SONS OF ALCOHOLIC FATHERS

A subgroup of abstinent alcoholics display low levels of plasma gamma- aminobutyric acid (GABA). Two previous studies of plasma GABA in sons of alcoholic fathers (SOAs) have yielded conflicting results. The aim of the current study was to measure plasma GABA both at baseline and a fter challenge with diazepam, a GABA(A) receptor agonist, in a group o f SOAs already shown to display decreased eye movement, memory, and se dative effects of diazepam. Twenty-seven SOAs and 23 male control subj ects received four logarithmically increasing doses of diazepam or pla cebo in randomized order on 2 days at least 1 week apart. Plasma GABA was measured at baseline and after the last dose. There were no signif icant differences between SOAs and controls in baseline plasma GABA le vels. In the whole sample, there were significant correlations between baseline plasma GABA and both high novelty-seeking and low-harm avoid ance scores on the Tridimensional Personality Questionnaire. Both SOAs and controls displayed decreases in plasma GABA over time on both tes ting days, but there was no effect of diazepam on plasma GABA and no s ignificant difference between groups in plasma GABA response to diazep am. These results suggest that neither low plasma GABA at baseline nor altered plasma GABA response to diazepam is associated with increased genetic risk for alcoholism.