The PHQ-9 scores nine items from 0 to 3, giving a total from 0 to 27. Scores of 5, 10, 15 and 20 mark the thresholds for mild, moderate, moderately severe and severe depression, and a score of 10 or above had 88% sensitivity and 88% specificity for major depression in the validation study.
That is where most summaries stop. The parts that change clinical decisions are underneath: the item 9 rule that ignores your total, the second scoring method most summaries skip, and the Australian wrinkle that decides whether your PHQ-9 data reaches the person reviewing your client's treatment plan.
How is the PHQ-9 scored?
The PHQ-9 is the nine-item depression module of the Patient Health Questionnaire. Each item asks how often, over the last two weeks, the person has been bothered by a given problem:
- Not at all = 0
- Several days = 1
- More than half the days = 2
- Nearly every day = 3
Add the nine items for a total between 0 and 27. Internal reliability in the original validation was strong: Cronbach's alpha of 0.89 in the primary care study and 0.86 in the obstetrics and gynaecology study, with a test-retest correlation of 0.84 when the questionnaire was repeated by telephone within 48 hours.
A tenth question asks how difficult the problems have made work, home life and getting along with other people. It is not part of the 0 to 27 total. It is a functional impairment item, and the one clinicians most often forget to record even though it frequently says more about the person's week than the score does. If someone returns a total of 11 and marks "extremely difficult", the impairment answer is the finding, not the 11.
What do PHQ-9 scores of 10, 15 and 20 actually mean?
The severity bands come straight from the validation paper: totals of 5, 10, 15 and 20 represent the cut points for mild, moderate, moderately severe and severe depression respectively. In practice that gives you:
- 0 to 4: minimal symptoms
- 5 to 9: mild
- 10 to 14: moderate
- 15 to 19: moderately severe
- 20 to 27: severe
The threshold that carries the most weight is 10, where the instrument reached 88% sensitivity and 88% specificity for major depression against a blinded mental health professional interview in a sample of 580 patients.
Two cautions. A cut point optimised for detection is not a recovery line: a client who moves from 24 to 11 has made a substantial change and is still above the threshold, and writing "still above cut-off" without the trajectory misrepresents the work. And the bands are descriptive labels attached to a symptom count, not diagnoses. The validation paper is explicit that before a final diagnosis the clinician is expected to rule out physical causes, normal bereavement and a history of a manic episode.
How do you score the PHQ-9 as a diagnostic algorithm?
The PHQ-9 has two scoring approaches, and the severity total is only one of them. The algorithm method works on the pattern of responses rather than the sum:
- Major depression is indicated if five or more of the nine symptoms have been present at least "more than half the days" over the past two weeks, and one of those symptoms is depressed mood or loss of interest.
- Other depression is indicated if two, three or four symptoms meet that same threshold, again with depressed mood or loss of interest among them.
Running both methods on the same form takes seconds and regularly produces a better formulation than either alone. A total of 14 built from nine items at "several days" is a different picture from a total of 14 built from four items at "nearly every day", though the severity band is identical. The first looks like diffuse low-grade distress; the second is narrower and more entrenched, and it is the one where the algorithm may cross the major depression threshold while the total sits mid-band.
What should you do when item 9 is not zero?
Item 9 asks about thoughts of being better off dead or of hurting yourself. It has its own rule: unlike the other eight symptoms, item 9 counts if present at all, regardless of duration.
That rule exists for the diagnostic algorithm, but the implication is broader. A response of 1 ("several days") on item 9 adds a single point to a total that may still land in the mild band. The total is not the trigger. Any non-zero response on item 9 warrants a risk assessment in that session, documented at the time, and a total of 6 does not soften that. The instrument has done its job by surfacing the response; it is not built to grade the risk, and no cut-off on the 0 to 27 scale should be read as permission to defer.
Our guide to documenting a suicide risk assessment covers what a defensible record of that conversation contains.
Does Medicare require the PHQ-9 in Australia?
No, and this is where Australian practice diverges from the American material that dominates search results. The outcome-measurement requirement sits with the referring doctor, not with you. The MBS explanatory note for GP Mental Health Treatment Plans (AN.0.56) states that preparing the plan must include "the administration of an outcome measurement tool (except if considered clinically inappropriate)". The choice of tool is at the practitioner's clinical discretion, but the examples the note actually names are the Kessler Psychological Distress Scale (K10) and the DASS 21. The PHQ-9 is not on that list.
The Better Access explanatory note, which governs the treatment sessions themselves, sets out eligibility, provider requirements and session rules, and imposes no outcome-measurement obligation on the treating psychologist. You are free to use the PHQ-9, and free to use nothing.
What catches people out is the review side. AN.0.56 requires that a plan review include "re-administration of the outcome measurement tool used in the assessment stage". The tool used at assessment was very likely the K10 or the DASS 21. If you have spent ten sessions tracking a PHQ-9 and report only that, the GP conducting the review is comparing against a measure you never collected, and your data sits outside the loop.
Treat them as doing different jobs. The K10 is a non-specific distress measure and is what the plan is likely pegged to; the PHQ-9 is depression-specific, with a symptom-level structure you can write objectives against. Collect the plan's tool so the review has its comparison, and run the PHQ-9 alongside it when depression is the target. Our guide to depression treatment plan goals and objectives works at the item level, the K10 scoring guide covers the measure the GP most likely used, and our note on mental health treatment plans and referrals covers what the referral itself must contain.
How should you track change across a course of treatment?
The PHQ-9 was validated as an outcome measure, not just a screener. In a follow-up study of 167 medical outpatients reassessed after a mean of 12.3 months, PHQ-9 change scores produced an effect size of -1.33 in the group whose depression status had improved, -0.21 in the unchanged group and +0.47 in the group that had deteriorated, with change scores differing significantly between the three groups.
Three habits make that property usable:
- Administer it the same way every time. Same point in the session, same mode. A form completed in the waiting room and later completed at home is not a clean comparison.
- Record the item profile, not only the total. A flat total concealing a drop in item 1 and a rise in item 6 is a clinical event.
- Interpret against the person's own baseline. The bands describe a population; the useful question is the distance travelled from this client's first administration, which is also the form the referring GP can act on when you write back to them.
PractaLuma is AI-native practice management software for Australian mental-health practices, and its standardised assessments library includes the PHQ-9, GAD-7, K10 and DASS-21, so the scored result and the item profile land in the client record rather than in a drawer.
When is the PHQ-2 or PHQ-8 the better choice?
Two shorter variants exist, and both have specific uses.
The PHQ-2 is the first two items, depressed mood and loss of interest, scored 0 to 6. Its validation study identified 3 as the optimal cut point for screening, with a sensitivity of 83% and a specificity of 92% for major depression. It is a triage instrument: use it to decide whether the full nine items are warranted, never as a severity measure.
The PHQ-8 is the PHQ-9 with item 9 removed. It was developed for general population research and telephone administration, where a positive suicidality response cannot be followed up safely in the moment. In clinical practice, where you can respond, that reasoning does not apply and the PHQ-9 is the right form.
Is the PHQ-9 free to use?
Yes. The instrument was developed by Drs Robert L. Spitzer, Janet B.W. Williams, Kurt Kroenke and colleagues with an educational grant from Pfizer Inc, and the footer carried on the official form states that no permission is required to reproduce, translate, display or distribute it. Translations and the related screeners are available at phqscreeners.com.
That is a real advantage over measures a practice might otherwise standardise on, and one reason the PHQ-9 appears in so many intake assessments.
Frequently asked questions
What does a PHQ-9 score of 12 mean? A 12 falls in the moderate band (10 to 14) and sits above the screening threshold for major depression. It indicates that a diagnostic assessment is warranted, not that a diagnosis is established. Check the item profile and the functional impairment question before drawing a conclusion.
Is a PHQ-9 score of 9 still significant? A 9 is the top of the mild band, one point below the cut point. Treat the cut point as a guide, not a boundary: a 9 driven by a non-zero item 9, or paired with "very difficult" on the impairment question, deserves the attention of a score in the band above.
Can a psychologist administer and score the PHQ-9 in Australia? Yes. The PHQ-9 is a self-report instrument and its publishers require no permission to reproduce or administer it. Administration and interpretation should sit within your scope of practice, and under Better Access the choice of measure is yours rather than a Medicare requirement.
Does the PHQ-9 diagnose depression? No. It produces a severity score and a criteria-based indication, both of which require clinical confirmation. The validation paper directs the clinician to exclude physical causes, normal bereavement and a history of a manic episode before any diagnosis is made.
How often should the PHQ-9 be repeated? There is no fixed rule. Because the items cover the last two weeks, administering it more often than fortnightly produces overlapping windows. Many practices settle on intake, a mid-point review and discharge, aligned with the review points in the treatment plan.
This article is general information for clinicians and is not clinical, legal or billing advice. MBS requirements change; confirm current item descriptors and explanatory notes at mbsonline.gov.au before relying on them.