RELATIONSHIP OF GENETICALLY TRANSMITTED ALPHA-EEG TRAITS TO ANXIETY DISORDERS AND ALCOHOLISM

We tested the hypothesis that a heritable EEG trait, the low voltage a lpha (LV), is associated with psychiatric disorders, Modest to moderat e evidence for genetic linkage of both panic disorder and the low volt age alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlat ion between these traits, A total of 124 subjects including 50 unrelat ed index subjects and 74 relatives were studied, Alpha EEG power was m easured and EEG phenotypes were impressionistically classified, Subjec ts were psychiatrically interviewed using the SADS-L and blind-rated b y RDC criteria, Alcoholics were four times more likely to be LV (inclu ding so-called borderline low voltage alpha) than were nonalcoholic, n onanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV, However, alcoholics without anxiety disorder were si milar to nonalcoholics in alpha power, An anxiety disorder (panic diso rder, phobia, or generalized anxiety) was found in 14/17 LV subjects a s compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielb erger Anxiety Scale, Familial covariance of alpha power was 0.25 (P < 0.01), These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparentl y not rare, because LV was found in approximately 10% of unrelated ind ex subjects and 5% of subjects free of alcoholism and anxiety disorder s. (C) 1995 Wiley-Liss, Inc.