This study will give researchers the opportunity to evaluate implementation of the Collaborative Behavioral Health Program (CBHP), based on the collaborative care model for depression, which aims to improve practice for physicians and staff; improve care for patients; and improve clinic operations through a model that allows for more efficient identification and referral for care for depression.

This study used a hybrid Type 2 effectiveness-implementation design of a randomized roll-out trial of the Collaborative Care Model for depression (CoCM) in 11 primary care practices in a large healthcare system affiliated with an academic medical center. The Collaborative Behavioral Health Program (CBHP) is supported by leaders in the healthcare system and the primary care steering committee as a means of improving access to effective mental health services. Implementation strategies including hiring and training the necessary staff for CoCM, audit and feedback procedures, and health information technologies to assist with billing and the patient registry, will be provided for all practices. Using a sequential mixed methods measurement approach, we will assess key stakeholders' perspectives of CBHP roll-out, focused on barriers and facilitators of implementation and sustainability. The Stages of Implementation tool will be used to measure the speed and quantity of implementation activities completed across the stages of implementation preparation, implementation, and sustainment over a 30-month period for each practice. Effectiveness of CBHP for patient-level outcomes will be conducted on depressive symptoms, graduation rates for CBHP, and spillover effects on chronic health conditions.

With its focus on implementation processes and strategies, this study will elucidate the critical drivers of CoCM implementation that are understudied for a program with such a robust evidence base. This study will also be among the first to conduct economic analyses on a fee-for-service model with the new billing codes for CoCM and can inform ways to improve implementation efficiency with our optimization approach to successive practices in the roll-out design. Changes to the protocol and current status of the study are also discussed.

Inclusion Criteria:

• PHQ-9 score > 10

Exclusion Criteria:

• Current suicidality
• Bipolar disorder
• Substance abuse disorder
• Psychosis
• Other severe mental health condition

Adult patients attending primary care appointments within the Northwestern Medicine health system's central region.