The Effect of Internet-Based Cognitive Behavioral Therapy (I-CBT) for Severe Fatigue in Adolescents with Immune Dysregulation Disorders: Preliminary Findings using a Multiple Single-Case Experimental Design.

Severe fatigue in adolescents with immune dysregulation disorders (IDD) is prevalent and affects daily functioning. This study tested Internet-based cognitive behavior therapy (I-CBT) for the treatment of persistent fatigue in adolescents with IDD. This study used a multiple single-case experimental design (SCED) with a randomized waiting list period of 7-26 weeks, followed by 26 weeks of I-CBT and a 16-week follow-up. Nine adolescents participated, focusing on fatigue severity as the primary outcome. Secondary outcomes included physical functioning, school absence, and, if applicable, pain severity. Pre-post-differences were examined across subjects and individually for weekly measures. At the group level, pre-post-differences in primary and secondary outcomes were examined using mixed models. The across-subject analyses demonstrated the expected effect for fatigue severity. Furthermore, there was a significant reduction in fatigue severity and school absence, and improvement in physical functioning. Single-case analyses demonstrated significant reductions in fatigue in 5/9 patients post-I-CBT, with improvements in physical functioning noted in 6/9 patients. Effect sizes ranged from medium to large. Pain severity significantly improved in 1/5 patients with a small effect size. In a sample of nine adolescents, results indicated that I-CBT could be an effective and feasible treatment of persistent severe fatigue in IDD.