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.