What is the PHQ-2?
The PHQ-2 (Patient Health Questionnaire-2) is an ultra-brief, two-item depression screening tool that asks about depressed mood and loss of interest (anhedonia) over the past two weeks, with each item scored 0-3 for a total possible score of 0-6. 1
Core Components
The PHQ-2 consists of the first two questions from the full PHQ-9 and specifically assesses: 2, 3
- Depressed mood: "Over the past 2 weeks, have you felt down, depressed, or hopeless?" 1
- Anhedonia: "Over the past 2 weeks, have you felt little interest or pleasure in doing things?" 1
Each question is scored from 0 ("not at all") to 3 ("nearly every day"), yielding a maximum score of 6. 2
Diagnostic Performance
At a cutoff score of ≥3, the PHQ-2 demonstrates a sensitivity of 73.7% and specificity of 75.2% for detecting major depressive disorder. 1 However, using a lower cutoff of ≥2 increases sensitivity to 86-91% while reducing specificity to 70-78%, capturing more true cases at the cost of more false-positives. 1, 4, 3
The largest validation study in primary care (2,642 patients) found that a PHQ-2 score ≥2 had 86% sensitivity and 78% specificity, while a score ≥3 had 61% sensitivity and 92% specificity. 4 A cutoff of ≥3 is recommended as the optimal threshold for screening purposes. 2, 1
Clinical Implementation: Two-Stage Screening Algorithm
The recommended workflow is to administer the PHQ-2 first as a rapid screen; patients scoring ≥3 should immediately receive the full PHQ-9 to assess severity and guide management. 1, 3 This gated approach requires only 1-2 minutes for the PHQ-2 compared with 3-5 minutes for the PHQ-9, reducing screening burden in busy primary care settings. 1
The two-stage method (PHQ-2 followed by PHQ-9 when positive) maintains similar sensitivity to using the PHQ-9 alone but significantly improves specificity and reduces the number of patients needing to complete the full questionnaire by approximately 57%. 3
Critical Limitation: Suicide Risk Assessment
The PHQ-2 omits the suicide item (item 9 of the PHQ-9), so relying on it alone can miss patients with suicidal ideation who may not endorse the two core depressive symptoms. 1 Consequently, clinicians should never use the PHQ-2 as the sole depression assessment tool and must follow any positive PHQ-2 screen with the full PHQ-9 to capture suicide risk. 1
In high-risk populations or when suicide screening is a priority, start directly with the PHQ-9 rather than the two-stage approach. 1
Implementation Requirements
Effective PHQ-2 screening programs require clear protocols for managing positive results; screening without defined intervention pathways does not improve patient outcomes. 1, 5 Key implementation elements include: 1
- Designated staff responsibilities for administering and scoring the PHQ-2
- Established referral pathways to mental health specialists for moderate-to-severe cases
- Availability of treatment resources for patients who screen positive
Distinction from Other Tools
The PHQ-2 should not be confused with other screening instruments such as the NCCN Distress Thermometer, the Generalized Anxiety Disorder Assessment (GAD-2 or GAD-7), or the Edinburgh Postnatal Depression Scale (EPDS), which are separate tools used for different screening purposes. 6