Participants received weekly one-hour CBT-AD sessions focusing on diabetes self-care and depression for approximately 10 sessions. Participants also had meetings with a registered dietitian and a nurse educator, focusing on nutritional management of diabetes and diabetes self-care education, respectively.

Cognitive-behavioral therapy for adherence and depression (CBT-AD) is a weekly, psychosocial treatment focusing on depression and patients' adherence to diabetes self-care. Treatment consists of weekly one-hour sessions for approximately 10 sessions.

We used electronic glucometers to measure participants' adherence to prescribed glucose self-monitoring, which record each time glucose was measured and the glucose level of each measurement.

We assessed adherence to participants' self-administered insulin through a self-report questionnaire.

Participants' depression severity was measured by clinician-administered measures (Montgomery-Asberg Depression Rating Scale) and self-report measures (Center for Epidemiological Studies Depression Scale). Clinician-delivered measures were administered at baseline and follow-up assessments by assessors blinded to participants' randomization status.

We measured participants hemoglobin A1C by means of a blood draw and laboratory test.