PHQ-9: Patient Health Questionnaire-9

Overview

The PHQ-9 is a nine-item adult depression screen covering the past two weeks. Survey Doctor adds nine frequency ratings for a total from 0 to 27 and reports five symptom bands. The score describes current symptom burden. It does not diagnose depression, explain its cause, or decide treatment.

Who should take this assessment?

The PHQ-9 can support an adult screening or symptom review when low mood, loss of interest, sleep changes, low energy, appetite changes, concentration problems, changes in movement, or thoughts of death or self-harm are concerns.

This page covers the adult English form. It does not cover the PHQ-A or other versions for teenagers, which need their own evidence for their wording and age group.

What to expect

The official English form asks nine questions about the past two weeks. Each answer uses the same frequency scale:

• Not at all: 0
• Several days: 1
• More than half the days: 2
• Nearly every day: 3

You need to answer all nine questions. The questionnaire usually takes only a few minutes, but take enough time to consider the full two-week period.

Score interpretation

The score is the sum of the nine answers, with no weighting or reverse scoring. The original validation study supports the five boundaries shown here.

These supported bands are descriptive. They do not prescribe care, and a low band never means that someone should stop existing care or avoid asking for help.

A boundary is not a cliff. One point can move a result into another band without showing a sudden clinical change, and the score cannot explain why symptoms occurred.

For a plain-language walkthrough, see what your PHQ-9 score means.

Item 9 and safety

Item 9 asks about thoughts of being better off dead or hurting yourself. Any answer above zero needs prompt, direct follow-up regardless of the total, but remains a safety signal rather than a complete suicide risk assessment.

If you need help now. In the US, Call 988 or text 988. Call 911 if you are in immediate danger. Outside the US, contact your local emergency number or find support in your country.

The optional difficulty question

Published PHQ-9 materials include an extra question about how much your symptoms make it hard to work, take care of things at home, or get along with other people. It has no score and is separate from the 0 to 27 total.

Survey Doctor asks it only when at least one of the nine answers is above zero. Your answer is saved with your result but never added to the score, and the score alone cannot tell you how much symptoms affect daily life.

What the questions measure

The nine items cover interest or pleasure, low mood, sleep, energy, appetite, feelings about yourself, concentration, movement or restlessness, and thoughts of death or self-harm.

These areas parallel depression symptom criteria. The questionnaire does not establish whether the symptoms form a disorder. It also does not rule out bipolar conditions, grief, physical illness, medication effects, substance effects, or another explanation.

The two-week window is deliberate. It provides a current symptom snapshot but does not show long-term course, recurrence, or what happened outside that period.

Using repeated scores

You can compare PHQ-9 scores over time when you take the same form under similar conditions. Look at the pattern rather than one change, and treat any change in item 9 as important whatever the overall direction.

There is no single point change, percentage change, remission rule, or retest interval that applies in every setting. Published approaches vary by population and purpose. Use an explicit, source-backed protocol when applying one.

Important limitations

• The total cannot diagnose depression or identify its cause.
• The difficulty question is optional and separate from the total.
• Physical illness, medication effects, substances, and life events can affect answers.
• A total recorded without the answers cannot show how item 9 was answered.
• A low score does not override a person's concerns or current care plan.

Evidence and population limits

The original PHQ-9 validation included 6,000 adult outpatients from eight primary care and seven obstetrics-gynecology clinics. A subset of 580 completed an independent structured interview with a mental health professional.

At a threshold of 10, sensitivity and specificity for major depression were both 88% in that interview subset (Kroenke et al., 2001). Those figures belong to the study population and method. They do not turn 10 into a diagnosis or guarantee the same performance in every setting, language, or age group.

Related assessments

PHQ-2: Patient Health Questionnaire-2:
A two-item depression screen drawn from the first two PHQ-9 items

GAD-7: Generalized Anxiety Disorder 7-item:
A seven-item screen for generalized anxiety symptoms

PHQ-15: Patient Health Questionnaire-15:
A questionnaire about physical symptom burden