Lactate infusions in panic disorder patients and normal controls: autonomic measures and subjective anxiety.

The anxiety symptoms, heart rate and blood pressure of 61 patients who panicked during lactate infusions were compared with 25 control nonpanickers. There was no significant difference in the increase in heart rate and blood pressure over baseline between patients and controls. There appeared to be no significant correlation between the subjective anxiety ratings and the measures of heart rate and blood pressure during lactate-induced panic. The symptoms of shortness of breath, feeling frightened or afraid, feeling dizzy and fear of losing control were significantly associated with lactate-induced panic. In addition, the cognitive symptoms of fear of losing control and fear of going crazy appear to be important determinants of lactate-induced panic.