An ultra-brief screening scale for anxiety and depression: the PHQ-4.

Background: The most common mental disorders in both outpatient settings and the general population are depression and anxiety, which frequently coexist. Both of these disorders are associated with considerable disability.

Objective: When the disorders co-occur, the disability is even greater. Authors sought to test an ultra-brief screening tool for both.

Method: Validated two-item ultra-brief screeners for depression and anxiety were combined to constitute the Patient Health Questionnaire for Depression and Anxiety (the PHQ-4). Data were analyzed from 2,149 patients drawn from 15 primary-care clinics in the United States.

Results: Factor analysis confirmed two discrete factors (Depression and Anxiety) that explained 84% of the total variance. Increasing PHQ-4 scores were strongly associated with functional impairment, disability days, and healthcare use. Anxiety had a substantial effect on functional status that was independent of depression.

Conclusion: The PHQ-4 is a valid ultra-brief tool for detecting both anxiety and depressive disorders.