Validated Patient Health Questionnaire-9 (PHQ-9) for depression screening and severity assessment. Automatic scoring and interpretation with suicide risk flagging.
The PHQ-9 (Patient Health Questionnaire-9) is the gold standard self-report instrument for depression screening and severity monitoring in clinical practice. This skill implements the complete PHQ-9 with automated scoring, DSM-5 criteria cross-referencing, suicide risk flagging on Item 9, and evidence-based treatment recommendations calibrated to severity level.
Major depressive disorder affects approximately 8% of adults in the United States in any given year and is the leading cause of disability worldwide. The USPSTF recommends screening all adults for depression in clinical practices with adequate systems for diagnosis, treatment, and follow-up (Grade B recommendation). The PHQ-9 has a sensitivity of 88% and specificity of 88% for major depression at a cutoff score of 10 (Manea et al., CMAJ 2012).
The PHQ-9 is a screening tool and does not establish a diagnosis. Item 9 screens for suicidal ideation and requires immediate clinical follow-up regardless of the total score. All patients endorsing suicidal thoughts must receive a comprehensive safety assessment.