Yohimbine challenge in children with anxiety disorders

Objective: The authors evaluated the neurohormonal and subjective mood resp onse of children with anxiety disorders who were challenged with yohimbine Method: Seventeen children with DSM-IV diagnoses of anxiety disorders and 1 5 normal comparison children were given yohimbine orally (0.1 mg/kg). Neuro hormonal measures and visual analog self-reports of tenseness were recorded over a 150-minute period. Results: Yohimbine was uniformly well tolerated, and it behaviorally differ entiated children with anxiety disorders from normal comparison children wi th higher maximum change (Delta max) ratings of anxiety in the patients (me an = 17.4 mm, SD = 29.8) than in the comparison subjects (mean = 0.3 mm, SD = 4.4). Yohimbine-stimulated Delta max growth hormone (GH) for children wi th anxiety disorders (mean = -1.5 ng/ml, SD = 5.9) was significantly reduce d compared to that of normal comparison children (mean = 2.7 ng/ml, SD = 4. 5). Conclusions: Yohimbine selectively elevates self-rated anxiety in children with anxiety disorders and is associated with the blunting of GH in those c hildren relative to that of comparison children. Presence of a blunted GH r esponse to yohimbine in children with anxiety disorders is reminiscent of f indings in adults with anxiety disorders, particularly panic disorder. Thes e findings support enhanced central adrenergic sensitivity in children with anxiety disorders, as demonstrated by yohimbine-exacerbated anxiety. The f indings should be reconciled with the absence of clonidine-related GH blunt ing in the same cohort.