516. Plasma GABA is inversely correlated with self-reported hostility: a preliminary report

Abstract

Decreased concentrations of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in brain, cerebrospinal fluid and plasma have been detected in patients with affective disorders, who often display aggressive behavior. In addition, preliminary reports indicate that psychopharmacological agents which elevate GABA show clinical efficacy in reducing aggression. In order to directly examine the relationship between plasma GABA (pGABA) and aggression, pGABA was measured and related to Buss-Durkee Hostility Inventory (BDHI) total scores in a mixed sample of adults (n = 82): those meeting DMS-III-R criteria for primary unipolar depression, bipolar disorder, or no axis I disorders. Overall, pGABA showed a negative correlation with hostility. First, BDHI scores were significantly higher in the subset of subjects whose pGABA levels were below a previously established normal range cutoff value of 100 pmol/mL. Second, plasma GABA levels showed a statistically significant negative relationship with BDHI scores, even after controlling for age, gender, liver enzymes, and DSM-III-R mood disorder. Finally, pGABA also showed a direct negative correlation with BDHI scores in persons not meeting DSM-III-R criteria for any Axis I disorder (Pearson r = −.390, p = .024). These preliminary data suggest that lower plasma GABA levels may be a trait characteristic of aggressiveness.