The relationship between irritable bowel syndrome and psychiatric disorders: from molecular changes to clinical manifestations

Abstract

Irritable bowel syndrome (IBS) is a functional syndrome characterized by chronic abdominal pain accompanied by altered bowel habits. Although generally considered a functional disorder, there is now substantial evidence that IBS is associated with a poor quality of life and significant negative impact on work and social domains. Neuroimaging studies documented changes in the prefrontal cortex, ventro-lateral and posterior parietal cortex and thalami, and implicate alteration of brain circuits involved in attention, emotion and pain modulation. Emerging data reveals the interaction between psychiatric disorders including generalized anxiety disorder, panic disorder, major depressive disorder, bipolar disorder, and schizophrenia and IBS, which suggests that this association should not be ignored when developing strategies for screening and treatment. Psychological, social and genetic factors appear to be important in the development of IBS symptomatology through several mechanisms: alteration of HPA axis modulation, enhanced perception of visceral stimuli or psychological vulnerability. Elucidating the molecular mechanisms of IBS with or without psychiatric comorbidities is crucial for elucidating the pathophysiology and for the identification of new therapeutical targets in IBS.

CHRFAM7A: a human‐specific α7‐nicotinic acetylcholine receptor gene shows differential responsiveness of human intestinal epithelial cells to LPS

“…To this end, studies of the CHRFAM7A locus on human chromosome 15 have historically focused on its association with schizophrenia (29,(57)(58)(59)(60)(65)(66)(67)(68)(69)(70), a prototypically human-specific disease, and not inflammation or epithelial biology. Yet, interestingly, schizophrenia is associated with changed risk for colon cancer and irritable bowel syndromes (71)(72)(73)(74)(75)(76)(77) and interestingly, a 2 bp mutation in CHRFAM7A. Whether these observations are functionally tied to nicotinic acetylcholine receptor activation and link nicotine to epithelial proliferation and permeability (15,37) is not known.…”

Gastroenterology issues in schizophrenia: Why the gut matters

“…As described in this section, it is well-established that the anticholinergic effects of first and second generation antipsychotics, and clozapine in particular, contribute to and compound GI motility issues such as constipation and bowel obstruction. Interestingly, while there exists substantial GI comorbidities in schizophrenia, the reverse may also be true, as increasingly psychiatric comorbidities are being reported in individuals with GI disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and celiac disease [36][37][38][39][40]. In this section, we review the motility effects of psychiatric medications, appraise current information regarding GI inflammation in schizophrenia as an inherent disease pathology and examine the overlapping epidemiology of the autoimmune disorder, celiac disease, and other dietary-based sensitivities with schizophrenia.…”

“…For example, in IBS, reportedly 19% of people with schizophrenia had IBS compared to a rate of 2.5% in the control group [37]. In the reverse analysis, up to 54 to 90% of IBS patients may have a psychiatric comorbidity, typically in the form of a mood or anxiety disorder [37,36]. Biochemical aids for the diagnosis of GI diseases such as Crohn's Disease include the measurement of antiSaccharomyces cerevisiae antibodies (ASCA) [50].…”

Psychological Interventions for Irritable Bowel Syndrome

“…So far, the exact mechanism explaining the interaction between IBS and psychological factors, their frequent association (even with psychiatric disorders) is not known, but recent data suggest that molecular or genetic changes could be involved [71]. Table II.…”