Sodium lactate infusions and panic attacks: a review and critique.

Response to sodium lactate infusions has been proposed as an experimental model and a biologic marker for panic attacks. Several authors have claimed that patients suffering from panic attacks, but not normal controls, "panic" in response to lactate. A careful review of methods and results of 13 studies, however, reveals serious methodologic problems, lack of specificity and sensitivity, and a failure to consider cognitive variables. When baseline differences are ruled out, the responses of patients and controls may not differ. So far, response to lactate cannot be interpreted as a model and marker for panic attacks and does not provide evidence for their underlying biologic distinctness from other types of anxiety. Known biologic mechanisms do not sufficiently explain the effects of lactate. Instead, an interaction of peripheral physiologic changes, past experience, environmental cues, and their appraisal as threatening or dangerous seems to be a more appropriate model.