Who is identified when screening for depression is undertaken in general practice? Baseline findings from the Diagnosis, Management and Outcomes of Depression in Primary Care (diamond) longitudinal study.

Objectives: To report the baseline characteristics of the Diagnosis, Management and Outcomes of Depression in Primary Care (diamond) study cohort and discuss the implications for depression care in general practice.

Design: A prospective longitudinal study beginning in January 2005.

Participants And Setting: Adult patients with depressive symptoms identified via screening with the Center for Epidemiologic Studies Depression Scale (CES-D > or = 16) in 30 randomly selected Victorian general practices.

Main Outcome Measure: Depression status on the Patient Health Questionnaire (PHQ).

Results: 789 patients form the cohort (71% women). At baseline, 47% were married, 21% lived alone, 36% received a pension or benefit, 15% were unable to work, 23% reported hazardous drinking, 32% were smokers, 39% used antidepressants and 19% used sedatives. 27% satisfied criteria for current major depressive syndrome (MDS) on the PHQ, while 52% had "persistent" depressive symptoms, and 22% had "transient" depressive symptoms, lasting at most a few weeks. Of those satisfying criteria for MDS, 49% were also classified with an anxiety syndrome, 40% reported childhood sexual abuse, 57% reported childhood physical abuse, 42% had at some time been afraid of their partner, and 72% reported a chronic physical condition; 84% were receiving mental health care (either taking antidepressants or seeing a health practitioner specifically for mental health care) compared with 66% of those with persistent depressive symptoms and 57% with transient depressive symptoms.

Conclusion: This method of screening for depressive symptoms in general practice identifies a group of patients with substantial multiple comorbidities -- psychiatric, physical and social problems coexist with depressive symptoms, raising challenges for the management of depression in general practice.