Supplementary Material for: Tailored Therapist-Guided Internet-Based Cognitive Behavioral Treatment for Psoriasis: A Randomized Controlled Trial

<p><b><i>Objective:</i></b> Patients with somatic conditions, such as psoriasis, frequently suffer from high burden of their disease in daily life and might benefit from internet-based cognitive behavioral therapy (ICBT) tailored to their adjustment problems. The aim of this multicenter randomized controlled trial was to examine the effects of therapist-guided, individually tailored ICBT in a clinical sample of patients with psoriasis. <b><i>Methods:</i></b> A total of 131 patients with psoriasis, who were screened for a psychological risk profile, were randomized to either care as usual (CAU, n = 66) or ICBT in addition to CAU (n = 65). Participants filled out standardized self-report questionnaires assessing physical and psychological functioning and impact on daily activities at baseline, posttreatment assessment, and 6-month follow-up. <b><i>Results:</i></b> In covariate-controlled linear mixed-model analyses, significantly larger improvements in ICBT compared to CAU were found in the primary outcomes physical functioning (p = 0.03, d = 0.36) and impact on daily activities (p = 0.04, d = 0.35), but not in psychological functioning (p = 0.32), up to 6 months after treatment compared to baseline. In explorative analyses, the working alliance measured at the beginning of ICBT treatment predicted improved physical (p = 0.02) and psychological (p < 0.001) outcomes. <b><i>Conclusions:</i></b> Results underline the promise of therapist-guided, individually tailored ICBT to improve physical functioning and reduce the impact of psoriasis on daily activities in patients with a psychological risk profile. Establishing a good therapeutic relationship early on may be an important factor that influences treatment outcomes in personalized ICBT interventions. Further research is needed to evaluate ICBT effectiveness in additional samples and to explore its underlying mechanisms.