Studies of psychological and/or pharmacological treatments aimed at treating depression in adults, children and adolescents who were diagnosed with depression or depressive symptoms and also had type 1 or 2 diabetes were eligible for inclusion. Studies had to report on depressive symptoms or depression as an outcome measure. Studies of diabetes education or adherence training were excluded.
The included studies considered psychosocial, pharmacological and collaborative care interventions. Collaborative care was defined as antidepressant medication and/or psychosocial intervention, usually in a stepped care or algorithm-based approach. Various depression outcome tools were utilised and included Beck Depression Scale (BDI), Mini International Neuropsychiatric Interview (MINI) and Hamilton Depression Rating Scale (HDRS) in patients with depressive symptoms or diagnosed depression. Depression entry criteria varied across studies. Types of treatment included cognitive-behavioural therapy (CBT), supportive psychotherapy, selective serotonin reuptake inhibitors (SSRIs), nortriptyline, bupropion and collaborative therapy, at various intensities and durations. Some studies also reported diabetes-related outcomes, including glycosylated haemoglobin A1c (HbA1c).
The authors did not state how many reviewers performed study selection.