EFFECT OF THE SELECTIVE SEROTONIN REUPTAKE INHIBITOR FLUVOXAMINE ON CCK-4 INDUCED PANIC ATTACKS

Data from animal studies suggest a functional relationship between the cholecystokinin-ergic (CCK) and the serotonergic (5-HT) system. There is increasing evidence that the cholecystokinin-4 (CCK4) challenge te st could be a valid experimental model for panic attacks in man. The a im of the present study is twofold; 1) to validate this model further and 2) to shed more light on the putative CCK\5-HT interaction. To thi s end, we studied the effect of the selective serotonin reuptake inhib itor (SSRI) fluvoxamine on CCK4-induced panic attacks. Twenty-six pani c disorder (PD) patients received, before and after a double blind 8-w eek treatment period with fluvoxamine (n = 17) or placebo (n = 9), a s ingle blind bolus injection with 50 mu g CCK4. Treatment with fluvoxam ine (150 mg daily) significantly decreased the sensitivity of PD patie nts for CCK4 while placebo was without effect. Of the patients who res ponded to treatment, 83% no longer experienced a panic attack when rec hallenged with CCK4, whereas in the non-responders group this was only 28%. In the fluvoxamine group the treatment response evaluated by the Hamilton Anxiety Scale (HAS) showed a statistically significant treat ment effect. The results of this study strengthen the validity of the CCK4 test as an experimental human model for panic attacks and yield e vidence supporting the hypothesis that both CCK and serotonin are impl icated in the regulation of anxiety.