Effects of citalopram treatment on behavioural, cardiovascular and neuroendocrine response to cholecystokinin tetrapeptide challenge in patients with panic disorder.

Eight patients with panic disorder were administered 20 micrograms of cholecystokinin tetrapeptide (CCK-4) before and after 8 weeks of treatment with the selective serotonin reuptake inhibitor (SSRI) citalopram. All patients responded to treatment by showing a significant general improvement and reaching a panic-free state for 2 weeks. At the rechallenge with CCK-4, patients displayed a marked reduction in the intensity and number of panic symptoms. The frequency of panic attacks induced with CCK-4 decreased by 50% after treatment. Citalopram treatment had no substantial effect on cardiovascular (heart rate and blood pressure) or hormonal (cortisol, prolactin and growth hormone) responses to CCK-4. Patients who still had panic attacks after treatment demonstrated a blunted growth hormone response to CCK-4 that was not seen in those who did not have panic attacks. This study suggests that treatment with an SSRI can reduce an enhanced sensitivity to CCK-4 without modifying cardiovascular and neuroendocrine responses to CCK-4 in patients with panic disorder.