PHQ-9 (Patient Health Questionnaire-9)
Why Use
Objectively determines severity of initial symptoms, and also monitors symptom changes and treatment effects over time.
When to Use
Use as a screening tool: To assist the clinician in making the diagnosis of depression. To quantify depression symptoms and monitor severity.
Formula
Pearls / Pitfalls
The Patient Health Questionnaire (PHQ)-9 is the major depressive disorder (MDD) module of the full PHQ. Used to provisionally diagnose depression and grade severity of symptoms in general medical and mental health settings. Scores each of the 9 DSM criteria of MDD as “0” (not at all) to “3” (nearly every day), providing a 0-27 severity score. The last item (“How difficult have these problems made it for you to do your work, take care of things at home, or get along with other people?”) is not included in score, but is a good indicator of the patient’s global impairment and can be used to track treatment response. Higher PHQ-9 scores are associated with decreased functional status and increased symptom-related difficulties, sick days, and healthcare utilization. May have high false-positive rates in primary care settings specifically (one meta-analysis found that only 50% of patients screening positive actually had major depression) ( Levis 2019 ).
Management
PHQ-9 Management Summary Score Depression severity Comments 0-4 Minimal or none Monitor; may not require treatment 5-9 Mild Use clinical judgment (symptom duration, functional impairment) to determine necessity of treatment 10-14 Moderate 15-19 Moderately severe Warrants active treatment with psychotherapy, medications, or combination 20-27 Severe
Critical Actions
Perform suicide risk assessment in patients who respond positively to item 9 “Thoughts that you would be better off dead or of hurting yourself in some way.” Rule out bipolar disorder, normal bereavement, and medical disorders causing depression.
Advice
Final diagnosis should be made with clinical interview and mental status examination including assessment of patient’s level of distress and functional impairment.
More Information
The PHQ-9 is a validated, 9-question tool to assess for the degree of depression present in an individual; the last question is not scored, but is useful functionally to help the clinician assess the impact of the patient's symptoms on his or her life.