Childhood abuse and treatment response in patients with irritable bowel syndrome: a post-hoc analysis of a 12-week, randomized, double-blind, placebo-controlled trial of paroxetine controlled release

Although irritable bowel syndrome (IBS) is frequently comorbid with childhood trauma, information on the clinical implications of this comorbidity is limited. We investigated whether a history of abuse was associated with response to treatment in a double blind, randomized, placebo controlled trial of paroxetine controlled release (CR) in IBS. Seventy-two IBS subjects were randomized to receive paroxetine CR (dose 12.5-50 mg/day) or placebo for 12 weeks. Subject selection was independent of abuse history. Sixty-one subjects completed the Sexual and Physical Abuse Questionnaire about their childhood abuse history. IBS symptoms were recorded using the Interactive Voice Response System (IVRS). Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Perceived Stress Scale (PSS) and Clinical Global Impression (CGI) were also measured. The primary outcome was treatment response defined as >= 25% reduction in composite pain scores (CPS) on the IVRS from randomization to end of treatment. The rate of abuse history was 50.8% (n = 31/61). Baseline demographic clinical characteristics (CPS, BDI, BAI, PSS, CGI scores) were not associated with abuse history. After 12 weeks of treatment, subjects with abuse history showed significantly higher CPS (t = 2.422, P = 0.018) than subjects without a history and less mean change of CPS (t = 3.506, P = 0.001). In a logistic regression analysis, history of abuse did not predict treatment response as measured by >= 25% reduction in CPS (OR = 0.481, CI = 0.164-1.406, P = 0.181), while the drug status (paroxetine CR) was significantly associated with treatment response as defined by a CGI improvement score of 1-2 (OR = 12.121, CI = 2.923-50.271, P = 0.001). Abuse history did not predict CGI-I (Fisher's exact, P = 0.500) improvements during the trial. History of abuse did not appear to have any significant clinical correlates at baseline and did not predict treatment response. Further studies are needed to confirm whether SSRIs are effective in IBS patients irrespective of their abuse history.