Response to lactate infusion in generalized anxiety disorder.

Intravenous sodium lactate infusion provokes symptoms of panic in patients with panic disorder at a significantly higher rate than in normal controls. Lactate sensitivity has been postulated to be specific for patients with panic attacks regardless of frequency of attacks or coexisting diagnoses. The authors present results of a pilot study of lactate infusions in patients with generalized anxiety disorder (GAD) without any history of panic attacks. Patients with GAD reacted more like panic disorder patients than like normal controls in anxiety and symptom scores during lactate infusion and in the rate of positive responses to lactate. Although preliminary, these findings raise questions regarding the specificity of lactate sensitivity and the relationship of GAD to panic disorder.