PLASMA GABA IN CHILDREN AND ADOLESCENTS WITH MOOD, BEHAVIOR, AND COMORBID MOOD AND BEHAVIOR DISORDERS - A PRELIMINARY-STUDY

Plasma GABA concentrations (pGABA) were measured in 115 inpatients (ag ed 7-17) with child psychiatric disorders. Group mean pGABAs were comp ared for 38 patients with mood disorders only (MOOD), 29 with behavior disorders only (BEH), 48 with comorbid mood and behavior disorders (M OOD + BEH), and 14 normal controls (CON, aged 14-17). The BEH group wa s characterized by (a) high mean pGABAs (157 vs. 133 pmol/ml), (b) low er mean pGABAs in BEH subjects who had been receiving pharmacotherapy with SSRIs or other medications (p < 0.026), and (c) decreased pGABA w ith increasing age (p = 0.019). These features were not found in contr ols or in groups of patients with mood disorders (MOOD or MOOD + BEH). Elevated mean pGABA in the BEH group appeared specifically in patient s with comorbid CD and ADHD, not in patients with ADHD or CD alone (p = 0.004). No patient in BEH (or CON) had pGABA below 100 pmol/ml, but low pGABAs were found in 15% of MOOD patients (who had no behavior dis order) and in 16% of MOOD + BEH patients. Pharmacotherapy did not chan ge pGABAs in the MOOD or the MOOD + BEH groups. No pGABA differences w ere found among the anxiety disorders, either alone or with mood or be havior comorbidity. The finding that plasma GABA levels are elevated i n nonmedicated behavior disorders that present in the absence of mood disorders, and appear to lower following medication treatments, merits increased attention to the pharmacological study of nonaffective beha vior disorders.