What PHQ-9 score counts as depression?

In the validation study by Kroenke and colleagues (2001), scores of 5, 10, 15, and 20 mark mild, moderate, moderately severe, and severe depression. A score of 10 or more was the point that best identified major depression against a clinician interview.

Does acting on regular scores actually improve depression treatment?

In a blind-rated trial by Guo and colleagues (2015), tying each treatment decision to regular scores and a guideline more than doubled remission compared with clinician judgment alone. The score only helps when someone reads it and acts on it.

Does showing therapists a patient's scores change outcomes?

Often, yes. A 2018 meta-analysis by Lambert and colleagues found that feeding progress scores back to therapists during care beat usual treatment in about two thirds of studies, with the largest gains for patients who were heading off track.

Maintenance

How accurate is the PHQ-9 for measuring depression?

Short answer

It is accurate enough to trust for a short questionnaire. In the study that validated it, a PHQ-9 score of 10 or higher flagged major depression correctly about 88% of the time, whether or not a person actually had it. Scores of 5, 10, 15, and 20 mark mild, moderate, moderately severe, and severe depression.

The research

Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a Brief Depression Severity Measure. Journal of General Internal Medicine, volume 16, issue 9, pages 606 to 613.

Sample About 6,000 primary care and obstetrics-gynecology patients across 15 clinics completed the PHQ-9, and 580 of them also had a separate interview with a mental health professional that served as the yardstick.

Published 2001

Journal Journal of General Internal Medicine

Kurt Kroenke, Robert Spitzer, and Janet Williams tested the PHQ-9, a nine-item questionnaire a person fills out about the symptoms of depression over the past two weeks. Each item is scored from 0 to 3, and the nine add up to a total from 0 to 27. About 6,000 patients across 15 primary care and women's health clinics completed it, and 580 of them also sat for a separate interview with a mental health professional, which served as the yardstick. Against that yardstick, a total score of 10 or more identified major depression with 88% sensitivity and 88% specificity. In plain terms, when the interview found depression the score caught it about 88% of the time, and when the interview found none the score agreed about 88% of the time. The authors set four thresholds, 5, 10, 15, and 20, to mark mild, moderate, moderately severe, and severe depression. As scores climbed, people reported worse daily functioning, more difficulty from their symptoms, and more sick days. The authors concluded the PHQ-9 is a reliable and valid measure of depression severity, brief enough for everyday care.

Read the paper

What does this mean for your clinic?

Accuracy is the right thing to ask about, because your clinic acts on the number. A score decides whether a patient gets flagged, whether a plan changes, and whether a case looks better or worse than last month. So the first question is simple: does the number reflect what is really going on?

The validation study says it mostly does. Measured against a trained interviewer, a score of 10 or higher caught major depression about 88% of the time, and cleared people who did not have it about 88% of the time. That is strong for a form a patient finishes in about two minutes. It is not perfect. Roughly one in eight results will point the wrong way, so a score is a signal to look closer, not a verdict on its own.

The four thresholds are what make the PHQ-9 useful for tracking over time, not just for a one-time check. Because 5, 10, 15, and 20 map to mild, moderate, moderately severe, and severe, a score you collect this month can be compared with the one from last month on the same scale. A number that drifts up is an early sign a patient may be sliding back, and a validated severity measure is what lets your care managers see that drift before it becomes a crisis visit. The study backs the scale up: as totals rose, daily functioning fell and sick days climbed, so the number is tracking something real in a person's life.

Now the honest limits. The PHQ-9 measures the severity of reported symptoms. It does not diagnose on its own, and it only reflects what a person is willing and able to put down on the day they fill it out. A cutoff is a trade-off: set it lower and you catch more real cases but also more false alarms. The numbers here come from primary care and women's health clinics in the United States around the year 2000, so your own population may read a little differently. Treat the score as a careful estimate that a clinician confirms, not as the final word.

This is also where the gap between visits shows up. A score taken only in the room tells you how a patient was doing on one day every few weeks. The same validated questionnaire, collected between visits, can show a rising score while there is still time to act on it.

The takeaway

A PHQ-9 score of 10 or more identified major depression about 88% of the time in its validation study, which is reliable for a two-minute form but not a diagnosis.
Because the thresholds of 5, 10, 15, and 20 are fixed, you can compare a patient's scores over time and catch a rising trend early.
Treat a single score as a flag to look closer, and have a clinician confirm it before you change a plan.

Terms in this page

Between-session support Mental readiness

This is the work Asendar™ was built for: collecting the same validated scores between visits and keeping them in front of your team, so a rising number shows up while there is still time to act, not at the next appointment.

See how Asendar™ works for clinics

Explore more in the Maintenance pillar