A randomized controlled trial examining the efficacy of an internet-based cognitive behavioral therapy program for adolescents with anxiety disorders

PLoS One. 2019 Sep 18;14(9):e0222485. doi: 10.1371/journal.pone.0222485. eCollection 2019.


Background: Anxiety disorders are highly prevalent in adolescence, but access to health care services is limited and only few receive professional help. Internet-based cognitive behavioral therapy (ICBT) has been proposed to increase accessibility and reduce costs of treatment.

Objective: The study evaluated the efficacy of a Danish version of the guided ICBT program ChilledOut Online, developed at the Centre for Emotional Health, Macquarie University, Australia.

Method: At the Centre for Psychological Treatment of Children and Adolescents, Aarhus University, Denmark, a randomized controlled trial was conducted with 70 adolescents (13-17 years) with anxiety disorders according to DSM-IV. Participants were randomly assigned to a 14-weeks therapist-guided ICBT or to a waitlist condition. Outcomes were evaluated post-treatment and at 3- and 12-month follow-up.

Results: At post-treatment, the ICBT group significantly outperformed the waitlist condition with moderate to large between-group effect sizes on diagnostic severity and anxiety symptoms rated by clinicians, and by adolescents and their parents. Forty percent of adolescents in ICBT were free of their primary diagnosis compared to 16% in the waitlist condition. Treatment gains were maintained at 3- and 12-month follow-up.

Conclusion: Results of the study provide support for the efficacy of guided ICBT for adolescents with anxiety disorders.

Trial registration: ClinicalTrials.gov: NCT02535403.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Anxiety / psychology*
  • Anxiety / therapy*
  • Anxiety Disorders / psychology*
  • Anxiety Disorders / therapy*
  • Australia
  • Cognitive Behavioral Therapy / methods
  • Cost-Benefit Analysis / methods
  • Denmark
  • Female
  • Humans
  • Internet
  • Male
  • Treatment Outcome
  • Waiting Lists

Associated data

  • ClinicalTrials.gov/NCT02535403

Grant support

The study was funded in part by Trygfonden (grant id: 100886) and by Edith and Godtfred Kirk Christiansens Fund (grant id: 21-5675). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.