Low plasma GABA is a stable trait marker of mood disorders

Abstract

unipolar types are at high risk for other psychiatric disorders. The data on the relationship of affective disorders to anxiety disorders have been inconclusive. Panic disorder, for example, has been seen as stemming from a common vulnerability with major depression (Breier et al., 1985) and as a separate disorder (Weissman et al., 1993). Recent evidence suggests a link with bipolar disorder (Savino et al., 1993). We have conducted a preliminary analysis of the clinical data obtained from 238 SADS-L interviews on the affected family members (41 BP !, 117 BP il, 4 Schizeaffective-manic type, and 76 Recurrent Unipolar Disorders) of bipolar probands ascertained for a genetic linkage study of bipolar disorder. Chi-squarc analysis was performed on the frequency of comorbid panic disorder in bipolar and unipolar subjects. For this analysis the diagnosis of panic disorder was applied if subject's symptoms met RDC inclusion criteria, whether or not there was concurrent depression. A significantly higher proportion of subjects with a bipolar disorder also had panic disorder, compared to subjects with recurrent unipolar disorder (14.8% versus 2.6%, chi square 7.89, df-i , p<.O05). The finding suggests a relationship between familial bipolar phenotypes (BP ! or II) and panic disorder symptoms. Whether this relationship is specific to a subset of bipolar families and why bipolar rather than unipolar family members are at greater risk merits further study.