Clinical utility of screening for clinical depression and bipolar disorder

Screening for clinical depression and bipolar disorder remains controversial. Screening is usually based on finding discriminating symptoms, but not all tools perform equally well. Clinicians should be able to assess the clinical utility of screening tests as well as their accuracy and acceptability.

Screening for depression using the Patient Health Questionnaire (PHQ) has been extensively examined. Four main versions of scoring the PHQ exist. The two-item PHQ2, the nine-item PHQ9, the PHQ DSM-IV algorithm, and the two-step PHQ2 then PHQ9. Recent results suggest that the PHQ9 is more accurate than the PHQ2, and that the algorithm scoring method is preferred to the linear cut-off score. The two-step procedure has promise, but it has not been adequately tested. Two screening questions may be a useful compromise in medical settings, as they take less than 2 min, but about a quarter of patients do not receive screening even when implemented systematically. Alternative customized questionnaires have been developed in medical settings such as the Depression Screening in Parkinson's Disease DESPAR and Neurological Disorders Depression Inventory for Epilepsy (NDDI-E). Screening for bipolar disorders is an even greater challenge than screening for unipolar depression. Screening in primary care and the community has low positive predictive value. Screening in high-risk samples, such as those with known depression is somewhat more successful, but not yet sufficiently accurate to be used alone.

Screening for depression can bring added value to routine unassisted recognition, but only if followed by good-quality treatment. Screening for bipolar disorder is not yet sufficiently accurate to be used reliably in clinical practice.