Who gets the most out of cognitive behavioral therapy for anxiety disorders? The role of treatment dose and patient engagement.

OBJECTIVE

The present study explored treatment dose and patient engagement as predictors of treatment outcome in cognitive behavioral therapy (CBT) for anxiety disorders.

METHOD

Measures of high versus low treatment dose and high versus low patient engagement in CBT were compared as predictors of 12- and 18-month outcomes for patients being treated for anxiety disorders with CBT (with or without concurrent pharmacotherapy) in primary care settings as part of a randomized controlled effectiveness trial of the Coordinated Anxiety Learning and Management (CALM) intervention. Measures of dose (attendance, exposure completion) and engagement in CBT (homework adherence, commitment) were collected throughout treatment, and blinded follow-up phone assessments of outcome measures (12-item Brief Symptom Inventory, Patient Health Questionnaire 8, Sheehan Disability Scale) were completed at 12 and 18 months. Propensity score weighting controlled for baseline differences in demographics and symptom severity between patients with high and low dose and engagement. These analyses included the 439 patients who selected CBT as treatment modality.

RESULTS

Completing exposures, having high attendance, and being more adherent to completing homework predicted better outcomes across all measures at 12 and 18 months, and high CBT commitment predicted better outcomes on all measures at 18 months.

CONCLUSIONS

This study found that higher treatment dose and patient engagement in CBT for anxiety disorders were stable and robust predictors of greater reductions in anxiety symptoms, depression symptoms, and functional disability.