Screening for depression in primary care

Depression has become one of the most prevalent mental disorders. Depressive disorders or significant depressive symptoms have been found in up to 25% of patients visiting general or family practitioners. Thus family doctors frequently meet depressive patients in their everyday work, and the importance of timely evidence-based diagnostics and treatment of the disorder has increased. The diagnosis of depression often presents difficulties, as it is time consuming and requires more clinical investigation. The recognition of depression on the primary care level could be improved by the availability of relevant diagnostic devices. Structured psychiatric interviews, e.g. Composite International Diagnostic Interview (CIDI), are reliable diagnostic instruments but these are too time consuming for family doctors and too elaborate for the routine use in primary care. Therefore, short self-rate questionnaires are proposed as screening devices of potential depressive patients in primary care. Self-rate instruments also enable the recognition of persons with minor depressive symptoms who form one of the risk groups for clinical depression. There is good evidence that screening improves the accurate identification of depressed patients in primary care settings. Self-rate instruments vary in the number of symptoms, by duration of the symptoms and by the scale of evaluation. The combination of symptoms in the self-rate instruments is also variable and it is still not clear which combination is best for the differentiation of healthy persons from depressive ones. The most commonly used screening measures for adults in primary care settings include the Beck Depression Inventory, the Zung Self-Depression Scale, the General Health Questionnaire (GHQ) and Patient Health Questionnaire-9 (PHQ-9). Screening by asking two simple questions about the mood and anhedonia was studied in order to facilitate the recognition of depression and it was discovered that these questions were as effective as using longer instruments. The aim of such type of studies was to provide as short and informative screening method of depression as possible which would be easier for patients and faster for GPs. In Estonia a screening scale for depression and anxiety, the Emotional State Questionnaire (EST-Q), which performs well on psychiatric patients and general population, has been developed. Nowadays a later modified version EST-Q2 is used. One purpose of the present study was to research the suitability of EST-Q2 screening scale depression subscale for screening of depression in general practice. The second purpose was to find out the combination of symptoms allowing the GPs to differentiate patients with depression from patients with other biomedical or psychosocial problems.