The patients were randomly assigned to an intervention group, which received optimal treatment for depression, including drug therapy, problem-solving treatment or both) for 12 months. The remaining patients were assigned to usual care from their primary care physician, with the proviso that they could see a mental health clinician if they wanted to.

Overall, the researchers detected no differences in diabetes self-management between the intervention and the usual care groups during the 12-year period.

"No difference was observed between the two groups in healthy nutrition, following a recommended diet, days with 30 or more minutes of continuous physical activity, days with specific exercise sessions, or smoking status," the authors note.
Patients in depression care intervention group actually had a slightly higher rate of nonadherence to prescription drugs for diabetes compared with the usual treatment group (nonadherent on 28.2 percent of days versus 24.0 percent of days, respectively).

However, the researchers say the findings do not imply that "depression care is not useful for improving diabetes self-management or outcomes."

They suggest that "integrated diabetes and depression care management, including specific support for diabetes medication adherence and self-care activities, as well as systematic depression care, can help patients achieve better psychological and diabetes outcomes."