Schizophrenia Raises Risk of Inflammatory Bowel Disease

Patients with schizophrenia are at increased risk of developing inflammatory bowel disease (IBD) compared with the general population, according to large study from Taiwan that provides more evidence of a gut-brain link.

The study also shows that patients with schizophrenia develop IBD at a younger age and that the risk increases with inadequately controlled schizophrenia.

"Physician vigilance and awareness of this correlation will improve IBD diagnosis and management among this vulnerable patient population," write Kuan-Yi Sung, Department of Medicine, Taipei Veterans General Hospital, and colleagues.

The study was published online in Alimentary Pharmacology and Therapeutics.

Greater Than Threefold Increased Risk

The prevalence of IBD, a chronic gastrointestinal disorder, is increasing around the world, and the exact etiology of the disorder remains unclear. Schizophrenia, a chronic and severe psychiatric disorder, affects nearly 1% of the global population.

Given mounting evidence of connections between the gut and the brain, Sung and colleagues investigated the risk of new-onset IBD in 116,164 patients with schizophrenia and 464,656 matched control persons, using the Taiwan national health insurance research database.

The overall incidence of IBD was significantly higher among patients with schizophrenia relative to matched control persons (1.14% vs 0.25%, P < .001). This was true for both ulcerative colitis (0.72% vs 0.12%, P < .001) and Crohn's disease (0.42% vs 0.13%, P < .001).

Patients with schizophrenia also developed IBD at a younger age than matched control persons (46.8 years vs 55.3 years; P < .001).

In adjusted analyses, patients with schizophrenia had a greater than threefold increased risk of developing IBD (hazard ratio [HR], 3.28; 95% CI, 2.49 – 4.33). IBD risk was higher for both ulcerative colitis (HR, 4.84; 95% CI, 3.32 – 7.07) and Crohn's disease (HR, 2.08; 95% CI, 1.37 – 3.15).

More patients with schizophrenia had moderate to severe IBD compared with control persons (36.8% vs 20.5%, P = .004).

"Interestingly, IBD risk was higher among patients with more severe schizophrenia, reflected by more frequent psychiatric hospitalizations," write the researchers.

The risk of developing IBD was also higher among patients with anxiety disorders but not among patients with other autoimmune diseases, obesity, smoking, bipolar disorder, or major depressive disorder.

Neither typical nor atypical antipsychotics use had an impact on IBD onset.

The researchers say their observations are in line with a previous study of hospitalized psychiatric patients from northern Finland, which found that IBD was significantly overrepresented in patients with schizophrenia.

Sung and colleagues say their study provides "the most robust and comprehensive evaluation of the risk for new-onset IBD among patients with schizophrenia."

Support for Gut-Brain Connections

Reached for comment, Miguel Regueiro, MD, chair of the Digestive Disease and Surgery Institute at Cleveland Clinic in Ohio, said, "This is an interesting study and is additional evidence that there may be a link between the brain and gut.

"There are other psychoneurologic diseases that have shown a similar association; for example, autism, dementia, and depression," said Regueiro, who was not involved in the study. "The brain-gut link may be interrelated for these diseases. We do not quite understand if there a causative relationship or if the microbiome in the gut in IBD and these neurologic and psychiatric conditions are linked.

"At this point, we would not screen all patients with schizophrenia for IBD, but we should have a heightened awareness to consider Crohn's disease or ulcerative colitis if a patient with schizophrenia develops gastrointestinal symptoms, such as pain, weight loss, rectal bleeding, or diarrhea," Regueiro advised.

The retrospective design is a limitation of the study, he noted, and he said that the study "cannot fully determine a true cause and effect.

"Additionally, the patient population is Taiwanese, and we do not know if this would be extrapolated to other populations," he said.

The study was supported by Taipei Veterans General Hospital, the Yen Tjing Ling Medical Foundation, and the Ministry of Science and Technology, Taiwan. The authors and Requeiro have disclosed no relevant financial relationships.

Aliment Pharmacol Ther. Published online March 8, 2022. Abstract

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