Correlation between digestive disease and psychiatric disease: casual or causal implication?

Abstract

The aim of this study was to evaluate the prevalence of psychiatric disturbances among patients affected with digestive diseases (both organic and functional) and, viceversa, the prevalence of digestive disturbances among patients with psychiatric diseases. We performed a trasversal study on: 100 patients with organic digestive diseases and 100 patients with functional digestive diseases afferent from a Gastroenterologic Ambulatory (gastroenterologic group); 50 patients afferent from a Psychiatry Service (psychiatric group) and 50 patients afferent from a General Medicine Ambulatory affected with a non gastroenterologic active problem (control group). Each patient underwent an anamnestic, laboratory and instrumental evaluation, in order to ascertain or exclude the presence of digestive symptoms and their eventual organic basis; moreover, a semistructured interview was performed aimed at identifying a psychiatric disturbance, according to DSM-IIIr criteria. Our results showed a significantly higher prevalence: 1) of psychiatric disturbances, in the gastroentorologic group versus the control group (p<0.001), especially of somatoform (p<0.05) and anxious (p<0.001) disorders; 2) of psychiatric disturbances among patients affected by functional digestive disorders versus patients affected by organic digestive disorders; 3) of gastroenterologic disorders, in the psychiatric group versus the control group (p<0.001), with a significantly higher prevalence of functional gastroenterologic syndromes in comparison the organic ones (p<0.001). The well-established bidirectional correlation between digestive functional and psychiatric disorders is a necessary but not sufficient condition to state a relationship of direct causality between the two syndromes; however we can hypothesize that the well documented neuro-hormonal alterations may cause, on clinical grounds different symptoms, that are differently interpreted by the different specialists (gastroenterologists or psychiatrists) consulted.