The U.S. Preventive Services Task Force recommends universal depression screening for all adults in primary care. Yet depression goes undetected in up to 50% of affected patients, not because clinics lack tools, but because workflows don't support systematic screening.
The PHQ-9 and PHQ-2 are validated, brief, and free. The challenge is fitting them into visits already packed with competing demands.
Why universal screening matters
Depression affects roughly 8% of adults each year, but many don't volunteer symptoms. Screening catches cases that symptom-based detection misses. The USPSTF recommends screening for all adults, including pregnant and postpartum persons, when systems exist to ensure appropriate follow-up. "Staff-assisted depression care" doesn't require integrated behavioral health; it means having a response pathway for positive screens.
Depression screening also ties to quality metrics: HEDIS measures, Medicare quality programs, and value-based contracts. Non-screening has reimbursement implications beyond clinical concerns.
Tiered screening: PHQ-2 first, PHQ-9 if positive
Universal full screening isn't practical. Every patient can't complete a full PHQ-9 at every visit. The tiered approach balances coverage with efficiency.
Step 1: PHQ-2 for everyone. Two questions, 30 seconds. The PHQ-2 asks about diminished interest and depressed mood over the past two weeks, scored 0-3 each. At a cutoff of >=3, sensitivity is 83% and specificity is 90%. Some practices use >=2 to catch more cases (sensitivity jumps to 91%, though specificity drops to 67%). A negative PHQ-2 ends screening for that visit.
Step 2: PHQ-9 for positive PHQ-2. Nine questions, 2-3 minutes. Confirms depression, assesses severity, and screens for suicidal ideation (item 9). With a cutoff of >=3 on PHQ-2, about 11% of patients need the PHQ-9. With >=2, that rises to 26%.
Workflow implementation
Who screens? Options include medical assistants during rooming (most reliable), tablets at check-in, paper in the waiting room, or electronic pre-visit via email or text (lower completion without prompting). Integrating screening with vital signs works better than treating it as a separate task.
When to screen? Annual wellness visits are natural opportunities. Screen new patients at baseline. Patients with risk factors (history of depression, chronic conditions, recent stressors, substance use) warrant more frequent screening. CMS requires that screening occur on the date of encounter or within 14 days prior.
Step-by-step:
1. EHR flags patients due for screening
2. During rooming, MA asks PHQ-2 questions or confirms patient self-completed
3. If score >=3 (or >=2 per your protocol), administer PHQ-9
4. Results documented in EHR before provider enters
5. Provider reviews results; positive screens flagged for attention
6. Clinical assessment and response during visit
Sample script for staff: "I'm going to ask you two quick questions about your mood that we ask all our patients." If positive: "Based on those answers, I'd like you to complete a few more questions so we can better understand how you're doing."
Responding to positive screens
A positive screen isn't a diagnosis. It's the start of clinical assessment.
PHQ-9 scores 5-9 (mild): Acknowledge and validate. Assess for medical causes, substance use, life circumstances. Discuss watchful waiting vs. intervention. Schedule follow-up in 2-4 weeks.
PHQ-9 scores 10-14 (moderate): Clinical evaluation for major depressive disorder. Discuss treatment options (therapy, medication, or both). Consider behavioral health referral. Document treatment plan.
PHQ-9 scores 15+ (moderately severe to severe): Full assessment. Active treatment discussion. Expedited referral consideration. For moderately severe to severe depression, combining psychotherapy and antidepressants may be more effective than either alone.
Item 9 response: Any score >0 on item 9 requires direct assessment regardless of total score. Ask about suicidal thoughts, assess specificity (passive thoughts vs. active plans), evaluate intent and access to means, and implement appropriate safety measures.
When to refer vs. manage in primary care
Refer to behavioral health: Patient prefers therapy, moderate-to-severe depression not responding to initial treatment, complex or comorbid presentation, suicidal ideation requiring specialty assessment.
Manage in primary care: Mild to moderate depression with straightforward presentation, patient preference, good response to initial treatment. Collaborative care models blur this distinction, since integrated behavioral health enables shared management.
Follow-up and measurement-based care
For patients starting treatment, readminister the PHQ-9 at 4-6 weeks, then every 4-8 weeks during active treatment. Track scores over time:
- 5-point improvement = clinically significant response
- Score below 10 = partial remission
- Score below 5 = full remission
Nearly half of patients prescribed antidepressants discontinue within the first month. Seeing patients 2-4 weeks after starting treatment, to assess response, reinforce education, and address side effects, improves adherence. Three contacts within 12 weeks is the recommended standard.
If no improvement after 6-8 weeks: Reassess diagnosis, evaluate adherence, consider comorbid conditions, and either intensify treatment or refer. Don't continue ineffective treatment indefinitely.
When patients decline treatment: Document that you discussed results and options, note their reasons if provided, and offer rescreening at a future visit. Respect autonomy while keeping the door open.
Common implementation challenges
"We don't have time." Pre-visit electronic screening uses no visit time. PHQ-2 takes 30 seconds during rooming. Positive screens justify additional time.
"Too many false positives." The PHQ-2 is sensitive by design. It's a screener. The PHQ-9 adds specificity. Clinical assessment determines need, not screening alone. Brief conversations after false positives have low cost.
"Patients resist the questions." Most accept screening when framed as routine: "we ask everyone." Some discomfort is acceptable for important health information.
"I'm not trained to treat depression." Mild to moderate depression is manageable in primary care with evidence-based treatments. Training is available and worthwhile. Referral resources exist for complex cases.
Measuring success
Process measures: Screening rate (target 80%+), timeliness of follow-up for positive screens, documentation completeness.
Outcome measures: Detection rate, treatment initiation rate for positive screens, PHQ-9 score improvement over time, referral completion rates.
Review metrics regularly: What's our current screening rate? Are positive screens getting appropriate follow-up? Where are patients falling through the cracks?
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Depression screening works when it's built into workflow rather than added on top. Automate the prompts, standardize the process, and track completion. The PHQ-2 catches most cases in 30 seconds; the PHQ-9 confirms and guides treatment. With a clear pathway from screen to intervention, detection rates improve and fewer patients slip through undiagnosed.