Depression screening: a practical strategy.

A 2-stage strategy, combining an assessment of severity with depression criteria, can help a physician focus on the most severe cases without missing less severe ones that still need treatment. Because of its brevity, relatively high positive predictive value, and ability to inform the clinician on both depression severity and diagnostic criteria, the PRIME-MD Patient Health Questionnaire (PHQ-9) is the best available depression screening tool for primary care. One-time screening is cost-effective; physicians may elect to screen more often based on risk factors.