PHQ-8: eight-item adult depression screen
The PHQ-8 asks about eight depression symptoms over two weeks and returns a 0-to-24 total. It omits PHQ-9 item 9 and collects no suicide or self-harm answer.
Overview
The PHQ-8 is an eight-item adult depression screen covering the past two weeks. Survey Doctor adds eight frequency ratings for a 0-to-24 total and five symptom bands. The questionnaire omits PHQ-9 item 9, so it collects no suicide or self-harm answer. It screens symptoms but does not diagnose depression.
If you are thinking about suicide or self-harm, seek support based on those thoughts. The PHQ-8 cannot record them.
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.
Act on it.
Introduction
Kroenke and colleagues studied the PHQ-8 as an adult general-population depression measure in 2009. Survey Doctor uses four frequency choices for each symptom.
The PHQ-8 is common in adult population research, and a clinical service may use it within a documented protocol when safety is handled separately. The missing item is an information gap, not a safeguard.
The gap remains.
Plan for safety.
Form and evidence boundary
The 2009 general-population study analyzed 198,678 adults in the US Behavioral Risk Factor Surveillance System. Its telephone survey asked for symptom days, then converted those answers to the PHQ's four frequency categories.
Survey Doctor asks the four categories directly. Both approaches produce 0-to-3 item values, but the administration methods are not identical.
Methods differ.
The study compared a score of 10 or higher with the PHQ-8's own DSM-IV-based algorithm. It did not use an independent structured diagnostic interview. Treat that result as population evidence, not proof that a total establishes a diagnosis.
That distinction matters.
Who should take this assessment?
The PHQ-8 may fit when:
- An adult population study specifies the categorical PHQ-8
- A healthcare provider selects it as one part of a broader assessment
- A protocol handles safety questions through a separate process
- Repeated research measurements need the same eight-item form
The PHQ-8 should not be chosen merely because immediate clinical follow-up is unavailable. A missing question cannot protect someone from risk.
Score interpretation
Each item scores from 0 to 3 based on symptom frequency during the past two weeks. All eight items are required in Survey Doctor, and the total runs from 0 to 24.
| Score | Current display label | What the range describes |
|---|---|---|
| 0-4 | None | The current lowest symptom-frequency band |
| 5-9 | Mild | A higher symptom-frequency band |
| 10-14 | Moderate | The middle symptom-frequency band |
| 15-19 | Moderately severe | A higher symptom-frequency band |
| 20-24 | Severe | The current highest band |
These are descriptive score bands. They do not diagnose depression, select treatment, or prove that care is unnecessary.
A total of 10 or higher is a commonly used screening threshold in adult studies. It is a reason for further assessment, not proof of major depression.
Survey Doctor uses five bands. Some US public-health reports combine scores from 15 through 24 into one severe group. Record the interpretation scheme when comparing published results.
Keep the scheme.
Record the scheme.
For a plain-language walkthrough, see what your PHQ-8 score means.
PHQ-8 compared with PHQ-9
The PHQ-8 and PHQ-9 share the first eight symptom items:
| Feature | PHQ-8 | PHQ-9 |
|---|---|---|
| Questions | 8 | 9 |
| Score range | 0-24 | 0-27 |
| Includes item 9 | No | Yes |
| Self-harm information | No | Yes |
The PHQ-9 can add up to three points from item 9. More importantly, it records an answer that the PHQ-8 never asks.
Do not infer a PHQ-9 item 9 answer from a PHQ-8 total. The two questionnaires also should not be treated as interchangeable for one person's score history.
No proxy exists.
Choosing between them
Choose the questionnaire that matches the documented protocol, population, and purpose. Adult population research often uses the PHQ-8. Some clinical protocols use the PHQ-9 because item 9 contributes separate safety information.
Neither choice replaces a direct safety assessment. If a person reports thoughts of suicide or self-harm elsewhere, respond to that disclosure regardless of which questionnaire was used.
Safety stays separate.
Administration
The PHQ-8 can be completed on paper, electronically, or in an interview. The method does not change its main limitation: no item asks about suicide or self-harm.
Survey Doctor requires all eight answers and does not prorate an incomplete form. The questions refer to the previous two weeks.
All eight count.
There is no single repeat schedule that fits every purpose. A research protocol or healthcare provider should define why and when another score is needed.
What the questions measure
The PHQ-8 covers several types of depressive symptoms:
- Mood and interest: Items 1 and 2 ask about enjoyment and feeling down or hopeless.
- Sleep, energy, and appetite: Items 3 through 5 ask about physical experiences that can occur with depression and other conditions.
- Self-view and concentration: Items 6 and 7 ask about feeling like a failure and trouble focusing.
- Psychomotor change: Item 8 asks about moving or speaking slowly, called psychomotor retardation, or fidgeting and restlessness, called agitation.
The direction of item 8 matters. Slowed movement or speech is retardation. Increased fidgeting or restlessness is agitation.
The questionnaire counts symptom frequency. It does not show why symptoms occurred, whether every diagnostic requirement is met, or how daily functioning has changed.
When to seek help
Talk with a healthcare provider when symptoms persist, worsen, or affect daily life. Do this at any score.
A PHQ-8 total cannot choose therapy, medication, or another treatment. A low total also does not mean that support is unnecessary.
If urgent safety concerns appear, act on them directly. Do not wait for a questionnaire that does not ask.
Evidence and validation
The 2009 study and later public-health implementations support the eight-item adult measure, two-week timeframe, 0-to-24 sum, and screening threshold at 10. They do not establish one best administration mode or one universal grouping scheme.
Performance varies by population, setting, and comparison interview. A score should be interpreted with evidence that matches the population rather than a single universal accuracy claim.
Important considerations
The PHQ-8 is a screening questionnaire, not a diagnostic test. Only a full assessment can determine whether depression or another condition explains the symptoms.
It does not assess suicide or self-harm. Omission of item 9 is a limit on the information collected, not an ethical or clinical safeguard by itself.
Medical conditions, medication, substance use, grief, stress, and other mental health concerns can affect the same symptoms. The total needs context.
Related assessments
Patient Health Questionnaire-9 (PHQ-9): The nine-item version, including item 9.
DASS-21: Depression Anxiety Stress Scales: A separate questionnaire covering depression, anxiety, and stress.
Generalized Anxiety Disorder 7-item (GAD-7): A questionnaire about common anxiety symptoms.
Patient Health Questionnaire-2 (PHQ-2): A two-item depression screen.
Related assessment information
These pages cover related assessments. They may measure different constructs or use different populations and recall periods.
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