Author information

1 Department of Clinical Neuroscience, Division of Psychology, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Stockholm Health Care Services, Stockholm County Council, Box 45436, SE-10431, Stockholm, Sweden; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, SE-171 77, Stockholm, Sweden. Electronic address: marianne.bonnert@ki.se.

2 Department of Medicine Solna, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Department of Pediatric Gastroenterology and Nutrition, Sachs' Children's Hospital, Södersjukhuset (KI SÖS), S1, Sjukhusbacken 10, SE-118 83, Stockholm, Sweden. Electronic address: ola.olen@ki.se.

3 Department of Clinical Neuroscience, Division of Psychology, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Norra Stationsgatan 69, SE-171 77, Stockholm, Sweden. Electronic address: johan.bjureberg@ki.se.

4 Stockholm Health Care Services, Stockholm County Council, Box 45436, SE-10431, Stockholm, Sweden; Department of Medicine Solna, Karolinska Institutet, SE-171 77, Stockholm, Sweden. Electronic address: maria.lalouni@ki.se.

5 Department of Clinical Neuroscience, Division of Psychology, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Department of Clinical Neuroscience, Osher Centre for Integrative Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden. Electronic address: kire.hedman@ki.se.

6 Stockholm Health Care Services, Stockholm County Council, Box 45436, SE-10431, Stockholm, Sweden; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Norra Stationsgatan 69, SE-171 77, Stockholm, Sweden. Electronic address: eva.serlachius@ki.se.

7 Department of Clinical Neuroscience, Division of Psychology, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Norra Stationsgatan 69, SE-171 77, Stockholm, Sweden. Electronic address: brjann.ljotsson@ki.se.

Abstract

Irritable bowel syndrome (IBS) is common in adolescents with a pronounced negative impact on quality of life. A pattern of avoidance behavior is commonly seen in the IBS population, which is associated with more gastrointestinal (GI) symptoms. Exposure-based cognitive behavior therapy (CBT) targets the avoidance behavior to reduce symptoms, but it is unknown whether reduced avoidance is a mediator of symptom improvement in adolescent IBS. Stress has been suggested to play a key role in worsening GI symptoms and is also a potential mediator of the treatment effect in IBS. This study was based on data from a randomized controlled trial (N = 101) that evaluated exposure-based internet-delivered CBT (Internet-CBT) compared with a wait-list for adolescents with IBS. We investigated whether avoidance behavior and perceived stress mediated the improvement in global GI symptoms due to treatment. We found that a change in avoidance behavior, but not perceived stress, mediated the effect of exposure-based Internet-CBT on GI symptoms. The decrease in avoidance behavior explained a large portion (67%) of the total treatment effect. Moreover, a unidirectional relationship over time was observed between avoidance behavior and GI symptoms. Our conclusion is that exposure-based CBT in adolescent IBS reduces avoidance and, consequently, reduces GI symptoms.