The role of treatment expectations in predicting treatment outcomes: examining clinical and demographic influences.

Objective: The primary aim of this study was to investigate the potential relationship between treatment expectancy and treatment compliance with patient demographic and treatment outcome of exposure-based CBT (EB-CBT), as reported by youth with OCD, their parents, and therapists. The secondary aim is to investigate the correlation of these factors with obsessive-compulsive symptoms before and after treatment.

Method: This study is a part of the NordLOTS, in which 269 children and adolescents, aged 7-17 years, with a DSM-IV diagnosis of OCD, were treated with a 14-week EB-CBT program. Patients, parents, and therapists rated their expectancy of the treatment, and therapists rated patients' and parents' compliance with treatment. A Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) score ≤15 was defined as treatment response. Linear mixed effects models were used to assess associations.

Results: Higher patient-rated treatment expectancy was significantly associated with lower pre-treatment CY-BOCS total score, as well as lower levels of parent-rated externalizing symptoms. Higher therapist-rated treatment expectancy was significantly associated with lower levels of parent-rated externalizing symptoms.

Conclusions: Children and adolescents displaying higher treatment expectancies exhibit milder symptoms of OCD and externalizing symptoms, alongside experiencing more favorable outcomes from EB-CBT.

Clinical trials registration information: This study was registered in Current Controlled Trials; Nordic Long-term Obsessive-compulsive disorder (OCD) Treatment Study (www.controlled-trials.com ISRCTN66385119).