PHQ-9 Depression Screener

What the PHQ-9 measures

The Patient Health Questionnaire-9 (PHQ-9), developed by Kroenke and colleagues and published in the Journal of General Internal Medicine in 2001, is the most widely used depression screening tool in primary care. It consists of 9 questions based directly on the DSM-5 diagnostic criteria for Major Depressive Disorder (MDD). Each question is scored 0 (not at all) to 3 (nearly every day), yielding a total score from 0 to 27. The PHQ-9 is free to use, requires no training to administer, and can be self-administered in about 2 minutes.

Score interpretation

Scores of 0-4 indicate minimal or no depression. 5-9 indicates mild depression, watchful waiting and self-care are typically sufficient. 10-14 indicates moderate depression, the threshold at which active treatment (counseling and/or medication) should be considered. 15-19 indicates moderately severe depression, active treatment is recommended. 20-27 indicates severe depression, immediate combination treatment is typically warranted. A score of ≥10 has a sensitivity of approximately 88% and specificity of 88% for Major Depressive Disorder.

The critical importance of item 9

Question 9 asks about thoughts of self-harm or suicide. Any response other than "Not at all" (i.e. a score of 1, 2, or 3) requires immediate clinical follow-up. A positive item 9 does not necessarily mean the patient is suicidal, but it warrants a thorough safety assessment by a trained clinician. In the United States, the Suicide & Crisis Lifeline can be reached by calling or texting 988. If you are in immediate danger, call 911 or go to your nearest emergency department.

How the PHQ-9 is used clinically

The PHQ-9 serves three purposes: (1) screening for depression in primary care and mental health settings, (2) establishing a baseline severity to guide treatment selection, and (3) monitoring treatment response over time. A 5-point decrease in PHQ-9 score is considered a clinically meaningful improvement. Remission is typically defined as a score <5. Most guidelines recommend repeat PHQ-9 every 4-8 weeks during active treatment, then every 3-6 months during maintenance.

Limitations and important caveats

The PHQ-9 is a screening tool, not a diagnostic instrument. A high score suggests depression but does not confirm it, a formal diagnosis requires clinical assessment including DSM-5 criteria, functional impairment, and rule-out of other conditions (bipolar disorder, grief, medical causes, substance use). The PHQ-9 does not screen for bipolar disorder, and antidepressants can trigger manic episodes in undiagnosed bipolar patients. It also does not assess anxiety, substance use, or other common comorbidities. The 2-week timeframe means it captures current state, not lifetime history. Always interpret results in clinical context and consult a healthcare professional for diagnosis and treatment.

If you need help

If you are struggling with depression or thoughts of self-harm, please reach out:

• United States: Call or text 988 (Suicide & Crisis Lifeline), available 24/7
• United Kingdom: Call 116 123 (Samaritans)
• Canada: Call or text 988 (Talk Suicide Canada)
• Australia: Call 13 11 14 (Lifeline)
• Emergency: Call 911/999/000 or go to your nearest emergency department