What the PHQ-9 actually is
The PHQ-9 is the depression module of the Patient Health Questionnaire. It was developed by Drs Robert L. Spitzer, Janet B.W. Williams and Kurt Kroenke with an educational grant from Pfizer Inc., and it is public domain — no permission is needed to reproduce or translate it. That is why you find the same nine items on a clinic clipboard, in an NHS waiting room and inside apps.
The nine items map onto the nine symptoms of a major depressive episode used in psychiatric diagnostic criteria, which the American Psychiatric Association describes as five or more symptoms present most of the day, nearly every day, for at least two weeks, with at least one of them being low mood or loss of interest. The questionnaire asks about the same ground. It does not decide anything.
Every item is scored 0 to 3: not at all, several days, more than half the days, nearly every day. Nine items, three points each, so the range is 0 to 27. A tenth question asks how difficult these problems have made work, home and relationships. That one is not added to the score. It is there because two people with the same number can be living very different weeks.
How the score is added up
There is no weighting and no clever maths. You add the nine numbers. That is the whole calculation.
The severity bands published with the instrument by Kroenke, Spitzer and Williams in the Journal of General Internal Medicine in 2001 are these:
- 0–4 — minimal symptoms
- 5–9 — mild
- 10–14 — moderate
- 15–19 — moderately severe
- 20–27 — severe
What the bands mean in practice
The band is a description of the last fortnight, not a label for you. It says how much symptom you reported, not why you reported it.
Below 10, the usual reading is that a full depressive episode is less likely right now. It does not mean nothing is wrong. Plenty of people score 7 and are having a genuinely difficult time. It means the questionnaire, on its own, is not pointing at depression as the explanation.
At 10 and above, the original validation study found the questionnaire performed at roughly 88 percent sensitivity and 88 percent specificity for major depression — which is why 10 is the number most clinics use as the point to look properly. Look properly means a conversation, not a conclusion.
At 15 and above, or when that tenth question says daily life is very or extremely difficult, the sensible next move is a prompt appointment rather than a wait-and-see. The World Health Organization notes that effective psychological and medical treatments for depression exist and that most people do not receive them. Getting seen is the bottleneck, not whether help works.
The ninth question is different
Item nine asks about thoughts of being better off dead or of hurting yourself. Any answer above not at all is treated on its own terms, whatever the total says. A score of 6 with a yes on item nine is not a mild week.
If that item is true for you tonight, that is the part to act on. Call or text 988 in the US, call Samaritans on 116 123 in the UK and Ireland, or find your country's free line at findahelpline.com. You do not owe anyone an explanation first, and you do not have to be sure you are in crisis to call.
What a score cannot tell you
A number can move for reasons that have nothing to do with depression. Grief. A thyroid problem. Anaemia. A new medication. Chronic pain. A newborn. Shift work. A genuinely awful month at a job you cannot leave yet. The questionnaire cannot see any of that; a person can.
It also cannot see the direction you are travelling in. A 14 on the way down from 20 and a 14 on the way up from 8 are the same number and completely different situations. One score is a photograph. What tells you something is a series of them.
And it cannot tell you what to do tomorrow morning. That is not a flaw in the instrument. It was built to flag, not to plan. The plan is a separate job, and it is the one that changes anything.
From a score to a next step
Take the number to someone. A GP, a nurse, a therapist, a campus health service. Say the score, say how long, say what has become hard. That is a complete opening sentence and it saves you having to find words at the worst possible moment.
Then take inventory of your life alongside it. Which parts have quietly gone — sleep, people, movement, something that was yours? A score tells you the weather. Naming what has slipped tells you where to put your hand.
That is the loop DepreScan is built around: scan, understand, reclaim. It screens, it never diagnoses. It gives you a snapshot, then a practical plan — one small step a day aimed at the specific parts of your life that went missing, rather than a chart of how bad you felt.
Questions people ask
Is a PHQ-9 score a diagnosis of depression?
No. The PHQ-9 is a screening questionnaire. It measures how often you have been bothered by nine symptoms over two weeks and produces a score from 0 to 27. Only a qualified health professional can diagnose depression, and they do it through a conversation that covers your history, your physical health, medications and what else is happening in your life. The score is useful evidence to bring to that conversation, not a substitute for it.
What is a normal PHQ-9 score?
Scores of 0 to 4 are described as minimal symptoms and are the most common result in the general population. There is no score that is medically 'normal' for a given person, though: someone who usually sits at 2 and is now at 8 has changed a great deal, even though 8 is still only the mild band. Direction of travel matters as much as the number.
Why is 10 the number everyone talks about?
Because that is where the original 2001 validation study by Kroenke, Spitzer and Williams found the best balance between catching real cases and not flagging people who are not depressed — roughly 88 percent sensitivity and 88 percent specificity for major depression. Most clinical services use 10 as the point at which they follow up properly. It is a threshold for a longer conversation, not a verdict.
Does the tenth question count toward the score?
No. The tenth item asks how difficult these problems have made work, home life and getting along with other people. It is recorded but not added to the 0–27 total. Clinicians use it because functional impact often changes what happens next: two people can both score 12, and the one who has stopped being able to work needs a faster appointment.
How often should I retake it?
Not daily. The questionnaire asks about the last two weeks, so retaking it every night mostly measures how tonight feels. Every two to four weeks is enough to see a trend, and that is what clinicians use it for when they are following someone's progress. If you want something to do daily, a twenty-second check-in is a better fit than a nine-item questionnaire.
Sources
- Kroenke K, Spitzer RL, Williams JBW. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16(9):606–613.
- American Psychiatric Association — What Is Depression?
- World Health Organization — Depressive disorder (depression) fact sheet
- National Institute of Mental Health — Depression