Follow-up study of control subjects with lactate- and isoproterenol-induced panic attacks.

Eleven of 45 normal control subjects experienced panic attacks during lactate and/or isoproterenol infusions. Ten of the 11 subjects were followed up for a mean period of 32.5 months. Two subjects reported the development of spontaneous panic attacks during the follow-up period; one related the development of these attacks to the infusion experience. Neither subject met DSM-III criteria for panic disorder either before or after the infusions. Twenty-six healthy control subjects who did not experience panic attacks during the infusion experience did not report any attacks during a follow-up period of 31.1 months.