Effects of repetitive transcranial magnetic stimulation (rTMS) on panic attacks induced by cholecystokinin-tetrapeptide (CCK-4).

Low-frequency (LF) rTMS shows beneficial effects in patients with depression and anxiety disorders. To explore its anxiolytic properties we investigated the effects of rTMS on experimentally induced panic attacks. Eleven healthy subjects underwent 1 Hz rTMS or sham rTMS over the right dorsolateral prefrontal cortex in a randomized cross-over protocol. Panic induction with 50 mug CCK-4 was carried out immediately after rTMS. Response to CCK-4 was assessed using the Acute Panic Inventory and the Panic Symptom Scale and measurements of heart rate, plasma ACTH and cortisol. All subjects reported a marked panic response following CCK-4 administration after both real and sham rTMS. Moreover, injection of CCK-4 induced a marked increase in heart rate, cortisol and ACTH concentrations. However, ANOVA showed no significant differences in any of the measures between both conditions. In contrast to the effects of pretreatment with alprazolam on CCK-4-induced panic in healthy subjects LF rTMS does not affect CCK-4-induced panic and cortisol or ACTH release.