When to Recheck PHQ-9 in Patients with Depression
Recheck the PHQ-9 at 3,6, and 12 months after initial screening, at regular intervals during treatment, with diagnosis of recurrence or progression, during times of personal transition or family crisis, and 5-12 weeks after starting antidepressant treatment to assess response. 1, 2
Initial Screening Timepoints
The American Society of Clinical Oncology guidelines specify clear intervals for PHQ-9 administration: 1
- At initial diagnosis or start of treatment 1
- At 3 months after treatment initiation 1, 2
- At 6 months after treatment 1, 2
- At 12 months after treatment 1, 2
- At diagnosis of recurrence or disease progression 1
- When approaching significant life transitions 1, 2
- During family crisis or periods of reappraisal 1
Treatment Monitoring Schedule
For patients on antidepressant medication, reassess with PHQ-9 at 5-12 weeks after initial treatment to guide clinical decision-making about treatment response. 3 This timing allows sufficient duration to evaluate medication efficacy while catching non-responders early enough to adjust treatment. 3
The PHQ-9 demonstrates excellent sensitivity to change over time, with effect sizes of -1.33 for patients whose depression improved, making it a valid tool for tracking treatment response. 4
Score-Based Monitoring Frequency
Your monitoring frequency should intensify based on severity: 1, 2
- PHQ-9 score 1-7 (minimal/mild): Reassess at future routine visits; no immediate follow-up required unless symptoms worsen 2, 5
- PHQ-9 score 8-14 (moderate): More frequent monitoring recommended, especially if referred to behavioral health 1, 6
- PHQ-9 score 15-27 (moderate-severe to severe): Close monitoring with repeat PHQ-9 at each treatment visit until improvement documented 1, 7
Special Monitoring Situations
Patients referred to integrated behavioral health require more intensive PHQ-9 monitoring, with an average of 2.1 follow-up assessments in 12 months, though this is still considered underutilization. 6 Those with chronic symptoms (elevated scores in the prior year) warrant more frequent reassessment. 6
Always reassess item 9 (self-harm thoughts) at every PHQ-9 administration, regardless of total score, as suicidal ideation can be present even with low overall scores. 2, 5, 7 This requires immediate emergency evaluation if endorsed at any level. 1, 2
Common Pitfalls to Avoid
Do not wait for scheduled intervals if clinical deterioration is suspected—administer the PHQ-9 whenever there is concern about worsening symptoms. 1 The tool takes only 2.3 minutes to complete and has minimal burden. 8
Avoid using the PHQ-9 solely at diagnosis without follow-up monitoring, as measurement-based care with serial PHQ-9 scores improves depression outcomes in primary care. 6 Underutilization of the PHQ-9 for monitoring is a documented quality gap. 6
Never modify the PHQ-9 items or scoring, as this weakens predictive validity and clarity of cutoff scores. 1