Family history of mental illness or alcohol abuse and the irritable bowel syndrome.

OBJECTIVE: We have observed that many patients with IBS drink very little alcohol and postulated that this may reflect membership in families affected by alcoholism and mental illness. We aimed to evaluate whether a family history of substance or alcohol abuse, or psychiatric illness, is associated with IBS.

METHODS: A valid GI questionnaire was mailed to a randomly selected population-based cohort to identify IBS and healthy controls. The electronic medical record was reviewed to record the subjects' self-reported personal and family health histories.

RESULTS: A total of 2300 subjects responded (response rate 55%; IBS 13%, n=287); 230 subjects with IBS and 318 controls were eligible. Family history of alcohol/substance abuse was reported by 33% of cases and 25% of controls (OR=1.4, 95% CI=1.0-2.1, p=0.06). Family history of psychiatric illness was reported by 37% of cases and 22% of controls (OR=2.0, 95% CI=1.3-2.9, p<0.001). In the absence of a personal history of alcohol use, a family history of alcohol/substance abuse was predictive of IBS status (OR adjusted for age and gender=1.5, 95% CI=1.0-2.3, p=0.05). In the absence of a personal history of alcohol use, reporting both a family history of alcohol/substance abuse and anxiety/depression/mental illness was clearly predictive of IBS status (OR=2.5, 95% CI=1.4-4.5; p<0.005). Substance abuse as a child was associated with an increased risk of IBS (OR=2.3, 95% CI=1.1-4.8; p<0.03).

CONCLUSION: IBS is independently associated with a family history of psychiatric illness and may be linked to a family history of alcohol/substance abuse.