Irritable bowel syndrome (IBS) and panic disorder coexist with a high frequency.
However, the nature of this relationship remains obscure.
Dr Diana Koszycki and colleagues from Ontario proposed that panic disorder and IBS may share a common dysfunction of the central cholecystokinin system.
The researchers assessed whether the enhanced panicogenic response to central cholecystokinin-tetrapeptide observed in panic disorder is also present in IBS.
The team included 8 psychiatrically healthy IBS patients, 8 patients with panic disorder with no history of IBS, and 12 normal controls.
The researchers gave the participants a bolus injection of central cholecystokinin-tetrapeptide or placebo on 2 separate days in a double-blind, randomized fashion.
Consistent with previous findings, panicogenic sensitivity to central cholecystokinin-tetrapeptide was enhanced in panic disorder patients vs controls.
|Central cholecystokinin-tetrapeptide induced nausea|
In contrast, the research team found that IBS patients exhibited a response that was comparable to controls.
Interestingly, the team observed that central cholecystokinin-tetrapeptide induced nausea.
Abdominal distress was decreased in IBS patients relative to the other groups.
The researchers noted no diagnostic difference for cardiovascular response to central cholecystokinin-tetrapeptide.
Dr Koszycki's team concludes, “These data indicate that IBS patients with no lifetime psychiatric history do not share the central cholecystokinin-2 receptor dysfunction implicated in the pathophysiology of panic disorder.”
“This dysfunction may not be a common mechanism for both the central nervous system and enteric nervous system disorders.”
“Nevertheless, the results suggest that a dysfunction of the central cholecystokinin system may be involved in the pathophysiology of some enteric symptoms associated with IBS.”