Screening and Treatment for Depression and Anxiety Using PHQ-9 and GAD-7
The PHQ-9 and GAD-7 are recommended as first-line screening tools for depression and anxiety symptoms in patients, with specific cutoff scores guiding assessment and treatment decisions. 1
Initial Screening Protocol
Depression Screening
- Step 1: Begin with the first two items of PHQ-9 (assessing low mood and anhedonia)
- Step 2: If either item scores ≥2 (occurring more than half the days), complete full PHQ-9
- Step 3: Interpret PHQ-9 total score:
- 0-7: None/mild symptoms
- 8-14: Moderate symptoms (≥8 is the recommended clinical cutoff) 1
- 15-19: Moderate-to-severe symptoms
- 20-27: Severe symptoms
Anxiety Screening
- Use GAD-7 for all patients
- Interpret GAD-7 total score:
- 0-4: Minimal anxiety
- 5-9: Mild anxiety
- 10-14: Moderate anxiety
- 15-21: Severe anxiety
Risk Assessment
- Immediate action required if patient endorses:
- Risk of harm to self/others
- Severe depression or agitation
- Psychosis or confusion (delirium)
- Action: Emergency referral to psychiatrist, psychologist, or equivalently trained professional 1
Treatment Algorithm Based on Severity
For Mild Depression/Anxiety
- Low-intensity interventions:
- Individually guided self-help based on cognitive behavioral therapy (CBT)
- Structured physical activity program
- Psychosocial group interventions
For Moderate Depression/Anxiety
- Consider consultation with psychology/psychiatry for diagnosis
- Treatment options:
- Group-based CBT
- Pharmacologic therapy as appropriate
- Address functional impairment
For Moderate-to-Severe/Severe Depression/Anxiety
- Referral to psychology and/or psychiatry for diagnosis and treatment
- High-intensity interventions:
- Individual psychological therapy delivered by licensed mental health professionals
- Pharmacologic therapy
- Relapse prevention strategies
Special Considerations
Timing of Screening
- Initial diagnosis/start of treatment
- Regular intervals during treatment
- 3,6, and 12 months after treatment
- At diagnosis of recurrence or progression
- When approaching end-of-life care
- During personal transitions or crises 1
Clinical Utility Considerations
- The PHQ-9 demonstrates good sensitivity (71-72%) but variable specificity (66-72%) for detecting depression 2, 3
- The GAD-7 shows good sensitivity (73%) but lower specificity (54-70%) for detecting anxiety disorders 2, 3
- Both scales are more useful as initial screening tools rather than diagnostic instruments 2
- Consider using higher cutoff scores in clinical populations (PHQ-9 ≥11) compared to community samples 3
Population-Specific Considerations
- Both PHQ-9 and GAD-7 have demonstrated utility in diverse populations:
- Transgender and gender nonconforming youth show high rates of positive screens (47% depression, 61% anxiety) 4
- Both measures have been validated across different cultural and linguistic contexts 5
- Brief versions (PHQ-2, GAD-2) can be used for ultra-rapid screening with a threshold of ≥3 indicating need for full assessment 6
Implementation Pitfalls to Avoid
- Don't omit the self-harm item from PHQ-9 as this may artificially lower scores and weaken predictive validity 1
- Don't rely solely on symptom counts without considering functional impairment and duration of symptoms 1
- Don't use screening tools as the sole basis for diagnosis - positive screens require further clinical assessment 2
- Don't overlook medical causes of depressive symptoms (e.g., interferon administration, thyroid disorders) 1
- Don't fail to reassess at key transition points in care and disease progression 1