PHQ-9 Age Range for Use
The PHQ-9 is validated and recommended for use starting at age 12 years through adulthood, including older adults. 1
Adolescent Population (Ages 12-18)
Universal depression screening with the PHQ-9 should begin at age 12 years, as endorsed by the U.S. Preventive Services Task Force (USPSTF) and the American Academy of Pediatrics GLAD-PC guidelines. 1
The PHQ-9 has been validated in adolescent primary care populations aged 12-18 years with a sensitivity of 89.5% and specificity of 77.5% at a cutoff score of 11 for detecting major depressive disorder. 1
Most treatment trials demonstrating efficacy of SSRIs and psychotherapy were restricted to adolescents aged 12-14 years or older, providing the evidence base for intervention effectiveness that justifies screening at this age. 1
The mean age of onset for major depressive disorder in childhood and adolescence is approximately 14-15 years, with earlier onset in girls than boys. 1
For adolescents specifically, the PHQ-9 Modified for Teens may be more appropriate when screening for depression in this age group. 1, 2
Evidence Gaps for Younger Children
No screening studies included children younger than age 11 years when the USPSTF evaluated the evidence for depression screening recommendations. 1
Studies examining depression screening in younger populations (ages 8-14 years) typically include depression as part of broader psychosocial screening rather than focused depression screening. 1
Adult Population
The PHQ-9 is widely validated and recommended for adults across all age ranges in primary care and specialty settings. 3, 4
The tool has been validated in cancer outpatients, where a cutoff of ≥8 may show better diagnostic accuracy than the traditional cutoff of ≥10. 3, 5
Older Adults (Ages 65+)
The PHQ-9 is suitable for detection and monitoring in older adults with mild cognitive impairment (MCI) and mild dementia. 3
The tool is quick (3-5 minutes) and has been validated in individuals with MCI/dementia, with scores of 5-9 suggesting mild depression, 10-14 moderate depression, and >14 moderately severe/severe depression. 3
The PHQ-9 becomes less suitable for more advanced and severe dementia and individuals with poor comprehension, as cognitive impairment can interfere with accurate self-reporting. 3
For older adults with more severe cognitive impairment, the Geriatric Depression Scale (GDS) may be preferable, as it is well-suited for detecting depression across the severity spectrum of MCI-dementia. 3
Critical Implementation Considerations
Never screen without established protocols for managing positive screens, as screening alone without intervention does not improve outcomes. 1, 5
Pay particular attention to item 9 of the PHQ-9, which assesses thoughts of self-harm—immediate referral is required for patients with specific plans or intent for self-harm. 1
Some clinicians inappropriately omit item 9 entirely, which artificially lowers scores and weakens predictive validity, particularly problematic given that item 9 is useful for stratifying risk of suicide attempt in adolescents. 5, 6
The PHQ-9 assesses symptoms over the past two weeks and was validated as a periodic assessment tool, not a daily symptom tracker, making it suitable for administration at strategic intervals such as initial screening, annual visits, or when clinical concern arises. 1