People with depression often suffer from comorbid chronic physical conditions and such conditions are widely believed to interfere with primary care providers' ability to recognize their depression. We aimed to examine the evidence related to the influence of chronic physical comorbidity burden on depression recognition in routine, community-based primary care settings.

We conducted a systematic review of the literature on depression recognition in primary care that featured comparisons between patient groups with higher and lower burdens of chronic physical comorbidity. Medline, Embase, PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials were searched from inception to July 2013. Reference list and reverse citation searches were also performed. A narrative synthesis was conducted given clinical and methodological heterogeneity between studies.

Our search identified 5817 unique citations, out of which we identified 13 studies reporting data on the relationship between chronic physical comorbidity burden and depression recognition in primary care. Four studies provided some evidence that higher chronic physical comorbidity burden negatively affected primary care providers' ability to recognize depression. In contrast, two studies reported higher rates of recognition in patients with higher comorbidity burden and seven studies reported no differences in recognition between comorbidity groups.

Chronic physical comorbidity burden does not consistently affect depression recognition negatively in primary care. Instead, recognition seems to vary depending on the specific conditions or combination of conditions examined. Methodological choices of authors, such as approaches to measuring recognition and chronic medical comorbidity, also likely explain some divergent results across studies.