Relationship of generalized anxiety symptoms to urinary 5-hydroxyindoleacetic acid and vanillylmandelic acid.

Urinary levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the norepinephrine metabolite vanillylmandelic acid (VMA) were measured in 45 patients with generalized anxiety disorder. Multiple regression analysis demonstrated that the severity of several anxiety symptoms was predicted by levels of 5-HIAA and VMA. These data are consistent with the proposal that serotonin and norepinephrine may be involved in the pathophysiology of anxiety.