What is the PHQ-2 Depression Screening?
The PHQ-2 is an ultra-brief, 2-question depression screening tool that asks about the two core symptoms of depression—depressed mood and loss of interest or pleasure—over the past two weeks, with each item scored 0-3 for a total score range of 0-6. 1, 2
Structure and Content
The PHQ-2 consists of the first two questions from the full PHQ-9 questionnaire 1, 3:
- Question 1: "Over the past 2 weeks, have you felt down, depressed, or hopeless?" 4
- Question 2: "Over the past 2 weeks, have you felt little interest or pleasure in doing things?" 4
Each question is scored from 0 (not at all) to 3 (nearly every day), yielding a maximum total score of 6 points 2, 5.
Diagnostic Performance
The PHQ-2 demonstrates good sensitivity but more modest specificity for detecting major depressive disorder:
- At a cutoff score of ≥3: Sensitivity of 73.7% and specificity of 75.2% for major depressive disorder 1, 4
- At a cutoff score of ≥2: Sensitivity increases to 86-91% but specificity drops to 70-78%, meaning more cases are caught but with more false positives 3, 6
The choice between these cutoffs depends on clinical priorities—use ≥2 when you cannot afford to miss cases, and ≥3 when you need to minimize false positives 6.
Clinical Application as a Gated Screening Tool
The PHQ-2 functions best as an initial screening step in a two-stage algorithm: administer the PHQ-2 first, and if the score is ≥3, follow with the full PHQ-9 to assess severity and guide management. 1, 4
This gated approach offers practical advantages:
- Takes only 1-2 minutes to complete versus 3-5 minutes for the full PHQ-9 2
- Reduces screening burden in busy primary care settings 1
- Maintains reasonable detection rates while reserving detailed assessment for those who screen positive 1
Critical Limitation: Suicide Risk Assessment
A major pitfall of using the PHQ-2 alone is that it completely omits the suicide question (item 9 of the PHQ-9), potentially missing patients with suicidal ideation who might not endorse the two core depressive symptoms. 1, 4
For this reason:
- Never rely on the PHQ-2 as your sole depression assessment tool 1
- Always administer the full PHQ-9 to positive PHQ-2 screens to capture suicide risk 4
- Consider starting directly with the PHQ-9 in high-risk populations or when suicide screening is a priority 1
Recommended Age Range
Universal depression screening with the PHQ-2 or PHQ-9 should begin at age 12 years and continue through age 18 years in adolescents, based on USPSTF and American Academy of Pediatrics guidelines 4, 7. The tool has been validated in adult populations of all ages, including older adults with mild cognitive impairment 4.
Implementation Requirements
Do not implement PHQ-2 screening without establishing clear protocols for managing positive results—screening alone without intervention pathways does not improve patient outcomes. 1, 4, 7
Essential implementation elements include:
- Designated staff responsibilities for administering, scoring, and acting on results 4
- Established referral pathways to mental health specialists for moderate-to-severe cases 4
- Treatment resources available for patients who screen positive 1, 7
- Protocols for immediate safety assessment when suicidal ideation is endorsed 4