Relationship between Negative Affectivity and Severity of Irritable Bowel Syndrome (IBS) Symptoms

Irritable bowel syndrome (IBS) is one of the common gastrointestinal disorders considered as a psychosomatic disorder. Type D personality characterized by both global traits including negative affectivity and social inhibition has been proposed to be related to etiology of psychosomatic disorders. However, the role of this personality type in severity of IBS symptoms remains unclear. The purpose of this study was to examine the role of type D personality in severity of IBS symptoms.

In a cross sectional study 194 consecutive patients with IBS referred to the psychosomatic clinics at Noor hospital, Isfahan were selected from Winter 2009 to Summer 2009. The patients were divided into two groups with (79 patients) and without (115 patients) type D personality by using DS-14. The patients completed type D personality Scale (DS-14) and the IB Severity Scoring System (IBS-SSS). Then the data was analyzed.

The findings indicated that 40.7% were the type D personality. Although the results of ANCOVA showed no significant difference between two groups, with and without type D, in severity of IBS symptoms (F=1.39, p= 0.24), multiple stepwise regression analysis indicated negative affectivity, as one of the type D dimensions (β= 4.03, p= 0.006) and treatment duration (β= 0.428, p= 0.038) were the significant predictors for severity of IBS symptoms.

Although, it seems that type D personality as a psychological factor does not effect on IBS symptom severity, the evidence confirms possible role of negative affectivity as one of the type D dimensions in severity of IBS symptoms.