Efficacy and cost-effectiveness of therapist-guided internet cognitive behavioural therapy for paediatric anxiety disorders: a single-centre, single-blind, randomised controlled trial.

Background: Paediatric anxiety disorders are associated with substantial disability and long-term adverse consequences, but only a small proportion of affected children have access to evidence-based treatment. Internet-delivered cognitive behavioural therapy (ICBT) could help increase accessibility but needs further rigorous assessment. We aimed to assess the efficacy and cost-effectiveness of ICBT in the treatment of paediatric anxiety disorders.
Methods: We did a single-blind randomised controlled trial in a clinical research unit within the Child and Adolescent Mental Health Services in Stockholm (Sweden). Eligible participants were children aged 8-12 years with a diagnosis of a principal anxiety disorder (seperation anxiety disorder, generalised anxiety disorder, specific phobia, social anxiety disorder, or panic disorder) of at least moderate severity. We randomly allocated participants (1:1) to ICBT or internet-delivered child-directed play, an active comparator aimed to improve parent-child relationships and increase a child's self-esteem without directly targeting anxiety. Block sizes for the randomisation varied between four and six and were generated using a computer random-number generator, and the allocation was concealed from the researchers by opaque sealed envelopes. Both treatment programmes comprised 12 modules presented over 12 weeks with weekly asynchronous online therapist support, and consisted of texts, films, illustrations, and exercises. The primary outcome was severity rating of the principal anxiety disorder 12-weeks post-treatment, via the Anxiety Disorder Interview Schedule for Diagnostic and Statistical Manual of Mental Disorders-IV (a rating of at least 4 corresponds to meeting the criteria for the principal diagnosis), assessed by clinicians masked to treatment allocation. All participants were included in the primary analysis (intention-to-treat). This trial is registered at ClinicalTrials.gov, number NCT02350257.
Findings: Between March 11, 2015, and Oct 21, 2016, 131 participants were recruited and allocated to either ICBT (n=66) or internet-delivered child-directed play (n=65). The clinician-assessed severity rating of the principal anxiety disorder improved significantly after the 12-weeks treatment period for participants in both ICBT (within-group effect size 1·22, 95% CI 0·78-1·65) and the active control (0·72, 0·44-1·00) groups. However, greater improvement was seen with ICBT than with the active control (estimated mean difference 0·79, 95% CI 0·42-1·16, p=0·002; between-group effect size 0·77, 95% CI 0·40-1·15). 29 (48%) participants in the ICBT group no longer had their principal diagnosis, compared to nine (15%) in the active control group (odds ratio 5·41, 95% CI 2·26 to 12·90, p<0·0001); the number needed to treat for ICBT to gain one additional participant in remission was three (95% CI 2·85 to 3·15). ICBT resulted in an average societal-cost saving of €493·05 (95% CI 477·17 to 508·92) per participant. No severe adverse events were reported.
Interpretation: ICBT is an efficacious and cost-effective treatment for paediatric anxiety disorders that should be considered for implementation in routine clinical care.
Funding: The Swedish Research Council for Health, Working Life and Welfare, and Stockholm County Council.
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