When children face fear: treatment, child, and family factors in cognitive behavioral therapy for childhood anxiety

Hagen, A. (2026)

Doctoral Thesis

Anxiety disorders are among the most common mental health problems in children and adolescents and can substantially interfere with their well-being and daily functioning. Although cognitive behavioral therapy (CBT) is an effective treatment, not all children benefit equally. This dissertation aimed to contribute to the optimization of CBT for childhood anxiety by examining treatment, child and family factors.
A central focus was on improving exposure-based treatment for children with specific phobias by supporting practice outside the therapy setting. We developed the Kids beat Anxiety (KibA) app to support children in carrying out exposure exercises at home following One-Session Treatment (OST), a brief and intensive CBT intervention for specific phobias. In a randomized controlled trial with 172 children, we compared OST followed by four weeks of app-supported homework with OST followed by standard homework support. Both groups showed substantial improvements in phobia symptoms, but adding the app did not lead to more homework practice or better treatment outcomes, although families reported greater satisfaction with the app.
The dissertation also examined child (self-efficacy) and family factors (family functioning) related to treatment response.

• Childhood anxiety
• Cognitive behavioral therapy
• Exposure
• Homework program
• Specific Phobia
• One-Session Treatment
• App
• Self-efficacy
• Family functioning

• All authors: Hagen, A.
• Supervisor: Klein, A.M.; Ollendick, T.H.
• Co-supervisor: Steensel, F.J.A. van
• Committee: Rombouts, S.A.R.B.; Jonge, M.V. de; Braet, C.; Farrell, L.J.; Legerstee, J.S.
• Qualification: Doctor (dr.)
• Awarding Institution: Institute of Psychology, Faculty of Social and Behavioural Sciences, Leiden University
• Date: 2026-09-15
• ISBN (print): 9789465345659
• Sponsorship: ZonMw