Comparing the Effect of Aripiprazole with Nortriptyline on Severity of Irritable Bowel Syndrome

Neuropsychiatric factors play important roles in symptoms of irritable bowel syndrome (IBS). Mood disorders such as bipolar disorder are prevalent among patients with IBS. Antidepressants are used traditionally for management of IBS symptoms but antibipolar agents have not been studied. Aripiprazole, an antibipolar agent, was selected because of having the least anticholinergic side effects. 147 patients with diagnosis of IBS were included in the study. Randomly selected 74 patients took nortriptyline 10 mg/day and 73 patients received aripiprazole 5 mg/day. Birmingham IBS Symptom Questionnaire for assessing the severity of IBS symptoms and Mood Disorder Questionnaire for diagnosis of bipolar mood disorder were filled by all the patients in the base time and then by 52 and 41 patients in month 1 and 40 and 28 patients in month 3, respectively. Two groups and subgroups of bipolar and nonbipolar disorders were compared in regard to the severity of IBS during follow-up visits. Decreases in mean scores were significant in both aripiprazole and nortriptyline groups during follow-up visits, but comparing the groups, the changes were more in aripiprazole group compared with nortriptyline group, although the differences were not significant (p > 0.05). The decrease in mean score was significant in both bipolar and non-bipolar subgroups during the follow-up visits, but the changes were only significant in bipolar subgroup of aripiprazole group (p < 0.05). Overall, aripiprazole has the same efficacy of nortriptyline in decreasing IBS symptoms but it is significantly more efficient in subgroup of patients with bipolar disorder. More and larger studies are needed for confirming the results of this study.