Diana Koszycki1, Stéphane Torres, James E Swain, Jacques Bradwejn. 1. Department of Psychiatry, University of Ottawa, and the University of Ottawa Institute of Mental Health Research, Royal Ottawa Hospital, Ottawa, Ontario, Canada. dkoszyck@rohcg.on.ca
Abstract
OBJECTIVE:Irritable bowel syndrome (IBS) and panic disorder (PD) coexist with a high frequency. However, the nature of this relationship remains obscure. We have proposed that PD and IBS may share a common dysfunction of the central cholecystokinin (CCK) system. To test this hypothesis, we assessed whether the enhanced panicogenic response to CCK-tetrapeptide (CCK-4) observed in PD is also present in IBS. METHODS:Eight psychiatrically healthy IBS patients, 8 PD patients with no history of IBS, and 12 normal controls received a bolus injection of CCK-4 and placebo on two separate days in a double-blind, randomized fashion. RESULTS: Consistent with previous findings, panicogenic sensitivity to CCK-4 was enhanced in PD patients relative to controls. In contrast, IBS patients exhibited a response that was comparable to controls. Interestingly, CCK-4-induced nausea and abdominal distress were decreased in IBS patients relative to the other groups. No diagnostic difference was noted for cardiovascular response to CCK-4. CONCLUSION: These data indicate that IBS patients with no lifetime psychiatric history do not share the CCK-2 receptor dysfunction implicated in the pathophysiology of PD and that this dysfunction may not be a common mechanism for both CNS and enteric nervous system disorders. Nevertheless, the results suggest that a dysfunction of the CCK system may be involved in the pathophysiology of some enteric symptoms associated with IBS.
RCT Entities:
OBJECTIVE:Irritable bowel syndrome (IBS) and panic disorder (PD) coexist with a high frequency. However, the nature of this relationship remains obscure. We have proposed that PD and IBS may share a common dysfunction of the central cholecystokinin (CCK) system. To test this hypothesis, we assessed whether the enhanced panicogenic response to CCK-tetrapeptide (CCK-4) observed in PD is also present in IBS. METHODS: Eight psychiatrically healthy IBSpatients, 8 PDpatients with no history of IBS, and 12 normal controls received a bolus injection of CCK-4 and placebo on two separate days in a double-blind, randomized fashion. RESULTS: Consistent with previous findings, panicogenic sensitivity to CCK-4 was enhanced in PDpatients relative to controls. In contrast, IBSpatients exhibited a response that was comparable to controls. Interestingly, CCK-4-induced nausea and abdominal distress were decreased in IBSpatients relative to the other groups. No diagnostic difference was noted for cardiovascular response to CCK-4. CONCLUSION: These data indicate that IBSpatients with no lifetime psychiatric history do not share the CCK-2 receptor dysfunction implicated in the pathophysiology of PD and that this dysfunction may not be a common mechanism for both CNS and enteric nervous system disorders. Nevertheless, the results suggest that a dysfunction of the CCK system may be involved in the pathophysiology of some enteric symptoms associated with IBS.