Distinct panicogenic activity of sodium lactate and cholecystokinin tetrapeptide in patients with panic disorder.

Background: The validity of experimentally induced panic attacks as a model to study the pathophysiology of panic disorder has been questioned. Unspecific, unpleasant and aversive effects as well as specific patterns of psychovegetative symptoms pointing to different subtypes of panic disorder patients have been observed. These findings raise the question of challenge paradigms as a valuable tool to identify different vulnerabilities in patients with panic disorder. Methods: We compared the two most widely studied panicogenic drugs sodium lactate and cholecystokinine tetrapeptide (CCK-4) with placebo in 25 patients with panic disorder and matched healthy control subjects. Psychophysiological changes were measured using the Acute Panic Inventory (API) and visual analogue scales for anxiety and arousal. Results: In patients with panic disorder 18 out of 25 experienced a sodium lactate- or a CCK-4 induced panic attack. Lactate or CCK-4 induced symptoms and induced panic attacks were only correlated in healthy controls, but not in patients with panic disorder. Conclusion: The mechanisms of lactate and CCK-4 induced panic attacks are distinct in panic disorder patients but not in healthy controls. Different neurobiological vulnerabilities may be uncovered by different challenges.