Effectiveness and prediction of treatment adherence to guided internet-based cognitive behavioral therapy for health anxiety: A cohort study in routine psychiatric care

Objective

Health anxiety, also known as hypochondriasis, is a common psychiatric disorder which leads to considerable distress and is associated with high societal costs. Internet-based cognitive behavioural therapy (ICBT) for health anxiety has demonstrated efficacy in randomized controlled trials (RCTs), but there is limited knowledge regarding its effectiveness in real-world settings. This study aimed to evaluate the clinical effectiveness of guided ICBT for health anxiety in routine psychiatric care, including symptom change, treatment adherence, and potential negative effects. Additionally, we explored predictors of treatment adherence.

Method

A longitudinal cohort study of 447 patients enrolled in 12 weeks of ICBT for health anxiety between 2018 and 2020 in an outpatient psychiatric clinic specializing in ICBT. Primary outcome measure was the 14-item Short Health Anxiety Inventory (SHAI-14) and a within-group design with repeated measures was utilized for the primary analysis.

Results

Participants showed significant improvements from pre- to post-treatment (d = 1.61). At post-treatment, 60 % (95 % CI 58–62) demonstrated statistically reliable change (RCI), and 44 % (95 % CI 42–46) were in remission. On average, participants completed 7 (SD = 4) out of 12 treatment modules. For each additional completed module, the mean reduction was 0.31 (95 % CI 0.10 to 0.54) points on the SHAI-14.

Conclusions

Guided ICBT for health anxiety can be effective when delivered within the context of routine psychiatric care. The study suggests that effect sizes are comparable with those in RCTs and higher treatment adherence is associated with better outcomes in health anxiety. ICBT could be used to increase availability to effective therapy for health anxiety.