Abstract
<title>Abstract</title> <p> Background Despite strong evidence for paediatric obsessive-compulsive disorder (OCD) treatment, children and adolescents with OCD do not typically receive these treatments at an adequate dose or fidelity. Children and adolescents with OCD are over-represented in hospital admission frequency and duration of stay yet have high readmission rates after discharge. Children with severe or complex OCD and co-occurring conditions who may have previous hospitalisations are often under-represented in research trials of psychological therapy. Methods This study examined the effectiveness of an 8-week community-based program including intensive exposure with response prevention (CBT-ERP) (2 weeks of monitoring and engagement, 2 weeks of intensive CBT-ERP, and 4 weeks of maintenance) for children with severe and complex OCD. Outcomes were evaluated for eleven children and adolescents (9 female) aged 10 to 17 years ( <italic>M</italic> = 14.82; <italic>SD</italic> = 2.27) with severe or extreme OCD, using a multiple baseline design for the primary outcome measure of OCD symptom severity. Non-parametric and descriptive analyses evaluated secondary outcomes of family accommodation, functional impairment and hospital admission rates. Results There were significant large treatment effects on OCD symptoms (clinician, parent, child-rated) and family accommodation (parent-rated), and a moderate effect on functioning (parent-rated). Between 54 − 27% of participants responded to treatment, depending on the rater, and 18–20% were remitters. No participants were hospitalised during treatment or 28 days after treatment. Conclusions In line with least-restrictive practice frameworks, this intensive CBT-ERP program was a suitable alternative to hospitalisation to provide effective and high-quality evidence-based treatment in the community for children with severe OCD. </p>