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Depression is one of the most common mental health conditions worldwide, and the PHQ‑9 is the most widely used short questionnaire to screen for it in primary care, hospitals, and research. The Patient Health Questionnaire‑9 (PHQ‑9) is a simple, 9‑item self‑report tool that helps identify possible depression and track symptom severity over time. If you want to see how it works in practice, you can take the PHQ‑9 test online on our home page and get an instant score interpretation.
What Is the PHQ‑9 Questionnaire?
The PHQ‑9 is a brief depression screening tool that asks how often you have experienced nine key symptoms of depression over the last two weeks. Each item is rated from 0 (not at all) to 3 (nearly every day), and the total score helps estimate how mild or severe your depressive symptoms might be.
PHQ‑9 Definition in Simple Language
The Patient Health Questionnaire‑9 (PHQ‑9) is a nine‑question form used to screen for, monitor, and measure the severity of depression symptoms. It is designed so that patients can complete it quickly on their own, and clinicians can interpret the score in seconds to decide whether further assessment or treatment is needed.
You can think of the PHQ‑9 as a structured checklist of core depression symptoms that turns how you feel into a simple number between 0 and 27. On phq9.app, this checklist is turned into an interactive PHQ‑9 test that automatically calculates your score and explains what it may mean.
Who Developed the PHQ‑9?
The PHQ‑9 was developed as part of the larger Patient Health Questionnaire by a team of researchers working with Pfizer, based on criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM). It was validated in large primary care and medical samples, showing that a short nine‑item questionnaire could accurately detect probable major depressive disorder.
Because of its strong research backing, ease of use, and free availability for clinical and research settings, the PHQ‑9 is now considered a gold‑standard depression screening tool worldwide. Many national guidelines recommend it for routine depression screening in general practice and medical clinics.
Who Is the PHQ‑9 For?
The PHQ‑9 was originally designed for adults in primary care and general medical settings, but it is now used in hospitals, community clinics, and mental health services as well. It is commonly used with adults, and modified versions or related tools are sometimes used for adolescents in school and youth mental health settings.
Clinicians use the PHQ‑9 to help decide whether someone might be experiencing clinically significant depression, and to monitor how symptoms change over time with treatment. Individuals can also complete the PHQ‑9 themselves online, such as through phq9.app, to better understand their symptoms before talking to a healthcare professional.
Key Features of the PHQ‑9
- 9 questions that map onto core symptoms of depression.
- Self‑report format that takes about 2–3 minutes to complete.
- Each question is rated from 0 to 3, giving a total score from 0 to 27.
- Widely used in primary care, hospitals, and mental health clinics worldwide.
- Free to use and supported by strong research evidence.
If you want to see these questions in action, you can start the PHQ‑9 test on our home page and get your score instantly, along with a clear explanation of your result.
How Does the PHQ-9 Work?
The PHQ-9 works by asking you to rate nine specific symptoms that are key diagnostic criteria for major depressive disorder. For each symptom, you indicate how often you have been bothered by it over the past two weeks, using a scale from 0 (not at all) to 3 (nearly every day). Your responses are then added together to produce a total score between 0 and 27, which helps estimate the severity of your depression symptoms.
The 9 Core Symptoms of Depression
Each of the nine questions on the PHQ-9 corresponds to one of the core symptoms used to diagnose major depressive disorder in the DSM (Diagnostic and Statistical Manual of Mental Disorders). These symptoms cover emotional, cognitive, physical, and behavioural changes that are common in depression, including loss of interest or pleasure (anhedonia), low mood, sleep problems, fatigue, appetite changes, feelings of worthlessness or guilt, concentration difficulties, psychomotor changes, and thoughts of self-harm.
The table below shows each PHQ-9 item, the symptom area it measures, and a brief description of what the question asks:
PHQ-9 Questions and Symptom Areas
| PHQ-9 Item | Symptom Area | Description |
|---|---|---|
| Question 1 | Anhedonia (loss of interest/pleasure) | Little interest or pleasure in doing things |
| Question 2 | Depressed mood | Feeling down, depressed, or hopeless |
| Question 3 | Sleep disturbance | Trouble falling asleep, staying asleep, or sleeping too much |
| Question 4 | Fatigue or low energy | Feeling tired or having little energy |
| Question 5 | Appetite changes | Poor appetite or overeating |
| Question 6 | Guilt or low self-worth | Feeling bad about yourself, like a failure, or that you have let yourself or your family down |
| Question 7 | Concentration problems | Trouble concentrating on things such as reading or watching television |
| Question 8 | Psychomotor changes | Moving or speaking so slowly that others could notice, or being so fidgety or restless that you have been moving around a lot more than usual |
| Question 9 | Suicidal thoughts or self-harm | Thoughts that you would be better off dead or of hurting yourself in some way |
Want to see how these questions look in practice? You can take the PHQ-9 test online on our home page and answer each question at your own pace.
Response Options and Time Frame
For each of the nine questions, you select one of four response options based on how many days you have experienced that symptom over the last two weeks:
- Not at all = 0 points
- Several days = 1 point
- More than half the days = 2 points
- Nearly every day = 3 points
The two-week time frame is important because it matches the diagnostic criteria for major depressive disorder, which requires symptoms to be present for at least two weeks. This standard time window also makes it possible to track changes over time by retaking the PHQ-9 every few weeks during treatment.
PHQ-9 Scoring: How to Calculate Your Score
Scoring the PHQ-9 is simple: you add up the points from all nine questions to get a total score ranging from 0 to 27. Higher scores indicate more severe depression symptoms. If you take the PHQ-9 test on phq9.app, your score is calculated automatically, so you don’t need to do the math yourself.
PHQ-9 Scoring System (0–27)
Each of the nine items is scored from 0 to 3, so the lowest possible total score is 0 (no symptoms) and the highest is 27 (all symptoms present nearly every day). The total score gives a quick snapshot of symptom severity and can be used to guide decisions about whether further assessment or treatment is needed.
PHQ-9 Severity Levels
The PHQ-9 uses standard cut-off scores to categorise depression severity into five levels. These thresholds were chosen because they are easy to remember and have been validated in research studies. The table below shows the standard interpretation:
| PHQ-9 Total Score | Depression Severity Level |
|---|---|
| 0–4 | Minimal or none |
| 5–9 | Mild depression |
| 10–14 | Moderate depression |
| 15–19 | Moderately severe depression |
| 20–27 | Severe depression |
A score of 10 or higher is commonly used as the cut-off to suggest clinically significant depression that may benefit from treatment. Research shows that at a cut-off of 10, the PHQ-9 has a sensitivity of 88% and a specificity of 88% for detecting major depressive disorder.
Example: Calculating a PHQ-9 Score
Let’s say you complete the PHQ-9 and give the following responses:
- Question 1: Several days (1 point)
- Question 2: More than half the days (2 points)
- Question 3: Nearly every day (3 points)
- Question 4: More than half the days (2 points)
- Question 5: Several days (1 point)
- Question 6: Not at all (0 points)
- Question 7: Several days (1 point)
- Question 8: Not at all (0 points)
- Question 9: Not at all (0 points)
Total score = 1 + 2 + 3 + 2 + 1 + 0 + 1 + 0 + 0 = 10
This score of 10 falls into the “moderate depression” category, which suggests that your symptoms may be significant enough to discuss with a healthcare professional.
Instead of calculating your score by hand, you can use our free PHQ-9 calculator on the home page, which gives you an instant result and explains what your score means in clear language.
How to Interpret Your PHQ‑9 Score Safely
The PHQ‑9 is a powerful depression screening tool, but it is not a stand‑alone diagnostic test. Your score reflects how many depressive symptoms you have experienced over the past two weeks and how often, but only a qualified clinician can diagnose major depressive disorder or other mental health conditions.
Using your PHQ‑9 score as a starting point for a conversation with a doctor, psychologist, or other mental health professional is usually the safest approach, especially if your symptoms are moderate or severe. If you complete the PHQ‑9 on phq9.app, you can use the score and severity category shown on the results page as a summary to bring to your appointment.
Screening Tool vs. Clinical Diagnosis
The PHQ‑9 was designed as a brief, evidence‑based questionnaire that helps flag people who may be experiencing clinically significant depression. It maps directly onto the diagnostic criteria for major depressive disorder, but it cannot capture everything a thorough clinical interview would explore, such as context, history, and differential diagnoses.
Clinicians typically use PHQ‑9 results together with a full assessment, including medical history, other mental health symptoms, and functional impact, before making any formal diagnosis. This is why even a high PHQ‑9 score should always be followed by a professional evaluation rather than used to self‑diagnose.
When to Talk to a Doctor or Therapist
In many studies and clinical guidelines, a PHQ‑9 score of 10 or higher is considered a threshold where depression is likely enough to warrant further assessment and possible treatment. Scores in the moderately severe (15–19) and severe (20–27) ranges are particularly strong signals that you should seek professional help as soon as you can.
Even scores in the mild (5–9) or moderate (10–14) range can be important if symptoms are persistent, getting worse, or impacting your work, studies, relationships, or daily functioning. After taking the PHQ‑9 on phq9.app, consider booking an appointment with your GP or a mental health professional if your results concern you or if you are unsure what to do next.
What If Your Score Is High on Question 9?
Question 9 of the PHQ‑9 asks about thoughts that you would be better off dead or of hurting yourself in some way, which makes it one of the most critical items on the questionnaire. Any score higher than 0 on this question is considered a serious warning sign that requires immediate attention, even if your total PHQ‑9 score is not in the severe range.
If you endorse thoughts of self‑harm or suicide, it is important to contact a crisis line, emergency service, or trusted healthcare provider right away rather than waiting. Online tools like phq9.app can help you recognise risk, but they cannot provide emergency support, so you should always follow local crisis guidance if you are in immediate danger.
Using the PHQ‑9 to Track Progress Over Time
One of the strengths of the PHQ‑9 is that it can be repeated regularly to monitor changes in depression severity. Many clinicians ask patients to complete the PHQ‑9 every two to four weeks during treatment so they can see whether symptoms are improving, staying the same, or getting worse.
By taking the PHQ‑9 on phq9.app at consistent intervals, you can build a simple timeline of your scores and use it as a visual record of your mental health journey to discuss with your doctor or therapist. This kind of tracking can be especially helpful when you start therapy, medication, or lifestyle changes and want to understand how they affect your mood over time.
Is the PHQ‑9 Accurate? Reliability, Sensitivity, and Specificity
The PHQ‑9 is one of the most thoroughly researched depression screening tools, with multiple studies confirming that it is both reliable and valid in a wide range of settings. Its widespread use in primary care, hospital clinics, and community surveys is largely due to its strong psychometric performance and ease of administration.
Research Evidence for the PHQ‑9
In the original validation study, the PHQ‑9 was tested in large primary care and medical samples and showed high internal consistency (reliability) and strong agreement with structured psychiatric interviews. Subsequent studies have replicated these findings in different populations, including older adults, people with chronic illnesses, and community samples, supporting its use as a general depression screening tool.
Because of this evidence, many national and international guidelines now recommend the PHQ‑9 as a standard instrument for identifying and monitoring depression in everyday clinical practice. It is also commonly used as an outcome measure in research trials that evaluate treatments for depression.
Sensitivity and Specificity for Depression
Sensitivity and specificity are two key statistics used to describe how accurate a screening test is at correctly identifying people with and without a condition. For the PHQ‑9, a commonly used cut‑off score of 10 or higher has been shown to provide a sensitivity of about 88% and a specificity of about 88% for major depressive disorder in primary care samples.
This means that at this threshold, the PHQ‑9 correctly identifies the vast majority of people who do have major depression (high sensitivity) while also correctly excluding most people who do not (high specificity). However, no screening tool is perfect, and there can still be both false positives (people flagged who do not have depression) and false negatives (people missed by the tool).
Strengths and Limitations of the PHQ‑9
The PHQ‑9 has several important strengths: it is brief, free to use, easy to score, and backed by strong research in many clinical and community settings. It can be self‑administered, which makes it ideal for digital tools like phq9.app, and its simple scoring system allows users and clinicians to quickly see whether symptoms might be mild, moderate, or severe.
At the same time, the PHQ‑9 has limitations that users should keep in mind. It focuses mainly on depressive symptoms over the past two weeks and does not assess other mental health conditions, life context, or physical health issues that might mimic or contribute to depression. This is why PHQ‑9 results should always be interpreted in context and ideally discussed with a healthcare professional rather than used in isolation to make important decisions about diagnosis or treatment.
Who Uses the PHQ‑9 and in What Settings?
The PHQ‑9 is widely used across different parts of the healthcare system because it is quick, free, and strongly validated. It helps clinicians and researchers screen for depression and track symptom changes over time using a simple, standardised score.
PHQ‑9 in Primary Care and Hospitals
General practitioners, internists, and other primary care clinicians use the PHQ‑9 to screen patients who present with low mood, fatigue, sleep problems, or vague physical complaints that might be related to depression. It is often built into routine check‑ups or chronic disease reviews (for example, in patients with diabetes, heart disease, or HIV), where depression can significantly affect treatment adherence and quality of life.
Hospitals and specialty clinics also use the PHQ‑9 to identify depression in patients being treated for other medical conditions. Because it is brief and easy to interpret, it fits well into busy clinical workflows and electronic health record systems.
PHQ‑9 in Mental Health and Therapy Settings
Psychiatrists, psychologists, and therapists frequently use the PHQ‑9 as a baseline and follow‑up measure to monitor how patients are responding to psychotherapy, medication, or combined treatment. Repeated PHQ‑9 scores can show whether symptoms are improving, staying the same, or worsening over time, which helps guide treatment adjustments.
Counsellors and digital mental health services may also integrate the PHQ‑9 into online intake forms or ongoing check‑ins. Tools like phq9.app allow users to complete the PHQ‑9 themselves, view a clear summary of their current symptom level, and then bring that information to a mental health professional for discussion.
PHQ‑9 in Research and Public Health
Researchers frequently use the PHQ‑9 in large population studies, clinical trials, and public health surveys to estimate how common depression is and how treatments perform in real‑world settings. Its strong psychometric properties and simple scoring make it especially useful when thousands of participants need a standardised measure of depression.
Public health programs and quality‑improvement initiatives sometimes track PHQ‑9 scores across clinics or health systems to evaluate how well they are identifying and treating depression. This widespread adoption has helped establish the PHQ‑9 as a gold‑standard depression screening tool globally.
PHQ‑9 vs Other Depression and Anxiety Tools
There are several brief questionnaires that screen for depression and anxiety, and understanding how the PHQ‑9 compares to them can help you see where it fits in. The PHQ‑9 focuses specifically on depression, while other tools target anxiety or provide ultra‑brief screening options.
PHQ‑9 vs GAD‑7 (Anxiety Tool)
The GAD‑7 (Generalised Anxiety Disorder‑7) is a seven‑item questionnaire designed to screen for generalised anxiety disorder rather than depression. It asks about excessive worry, nervousness, restlessness, and related anxiety symptoms over the last two weeks, using the same 0–3 response scale as the PHQ‑9.
Clinicians often use the PHQ‑9 and GAD‑7 together because depression and anxiety frequently occur at the same time. On a site like phq9.app, you can start with the PHQ‑9 for depression and later explore dedicated anxiety tools if you and your clinician think they would be helpful.
PHQ‑9 vs PHQ‑2
The PHQ‑2 is a shorter version of the depression screener that includes just the first two items of the PHQ‑9: low interest/pleasure and depressed mood. It is used as a very quick initial screen in busy settings, such as primary care or emergency departments, to decide whether a full PHQ‑9 should be completed.
If a person scores above a certain threshold on the PHQ‑2, they are usually asked to complete the full PHQ‑9 so that depression severity can be assessed more accurately. This two‑step approach balances speed with the need for a more detailed severity measure.
Comparison Table: PHQ‑9 vs PHQ‑2 vs GAD‑7
| Tool | Main Focus | Number of Items | Typical Use |
|---|---|---|---|
| PHQ‑9 | Depression | 9 | Screening and monitoring depression severity |
| PHQ‑2 | Depression | 2 | Ultra‑brief initial depression screen |
| GAD‑7 | Generalized anxiety | 7 | Screening and monitoring anxiety symptoms |
In most cases, the PHQ‑9 is preferred when a more detailed picture of depression symptoms and severity is needed, while the PHQ‑2 is used as a quick filter and the GAD‑7 focuses specifically on anxiety.
How to Take the PHQ‑9 Test Online (Safely)
Taking the PHQ‑9 online can be a convenient way to understand your current level of depression symptoms before talking with a professional. However, it is important to use a trustworthy tool and to know what your results can and cannot tell you.
Step‑by‑Step: Taking the PHQ‑9 on phq9.app
- Go to the home page
- Visit the phq9.app home page, where the PHQ‑9 test is available as an interactive questionnaire.
- Answer the 9 questions honestly
- View your total score and severity level
- Read the suggested next steps
- Use the result as a conversation starter
- You can save or write down your score and discuss it with your GP, psychologist, or another mental health professional to decide on appropriate next steps.
Privacy and Data Considerations
Because the PHQ‑9 asks about sensitive mental health information, it is important to consider how your data is handled when you use any online tool. Ideally, the site should clearly explain whether responses are stored, how long they are kept, and whether they are linked to any identifying information.
If phq9.app is designed not to store personal identifiers alongside scores, this can help protect your privacy while still allowing you to benefit from automated scoring and interpretation. Regardless of the platform, you should avoid using public or shared devices for mental health questionnaires and always log out or close the browser tab when finished.
When the PHQ‑9 Is Not Enough
Although the PHQ‑9 is a robust, evidence‑based tool, there are situations where it does not capture the full picture. Context matters, and scores need to be interpreted carefully, especially when symptoms are related to life events or physical health problems.
Situations Where the PHQ‑9 Can Be Misleading
Stressful life events such as bereavement, relationship breakdown, job loss, or physical illness can temporarily increase PHQ‑9 scores even if a person does not meet full criteria for major depressive disorder. Conversely, some people may under‑report symptoms because of stigma, lack of insight, or difficulty recognizing emotional experiences, resulting in scores that appear lower than their true level of distress.
Medical conditions (for example, chronic pain, thyroid problems, or sleep disorders) can also contribute to symptoms such as fatigue, sleep disturbance, and concentration problems, which can increase PHQ‑9 scores even when depression is not the primary issue. This overlap is another reason why professional interpretation is so important.
The Importance of Clinical Judgment
Because of these complexities, PHQ‑9 results are intended to inform clinical decision‑making rather than replace it. Clinicians consider the PHQ‑9 score alongside other information such as duration of symptoms, functional impairment, past history, and the presence of other mental or physical health conditions.
For users of phq9.app, this means that the online score should be viewed as a helpful indicator and conversation starter, not a final answer. If your results worry you, or if you are unsure what they mean for your situation, bringing your score to a professional is usually the safest and most effective next step.