The authors administered lactate to 12 abstinent alcoholics with panic disorder, 10 nonalcoholic patients with panic disorder, and eight control subjects. They found that the alcoholic patients had fewer panic attacks in response to lactate infusion than the nonalcoholic patients. This finding was not attributable to differences in baseline anxiety or the change in plasma chemical values brought about by sodium lactate administration. The authors suggest that there may be subgroups of patients with panic disorder who need further characterization to meaningfully elucidate the pathophysiology of the disorder.