• Depression
• Mental Health

How Does the PHQ-9 Work?

Published: July 25, 2025
Updated: July 25, 2025
5 mins

The PHQ-9 is a simple, research-backed questionnaire that can help you better understand what you’re feeling and whether it might be linked to depression. Used by doctors and mental health professionals around the world, the PHQ-9 test offers a fast, straightforward way to screen for symptoms and track how they change over time.

In this guide, we’ll break down what the PHQ-9 is, how it was developed, what the questions mean, how the scoring works, and what your PHQ-9 score might tell you. Whether you're taking the test yourself or just curious about how depression screening tools work, you’ll find everything you need to know right here.

What is the PHQ-9?

The PHQ-9 (or Patient Health Questionnaire-9) is a widely used self-administered screening tool designed to help identify symptoms of depression. It was developed for use in both clinical and primary care settings to offer a quick, evidence-based method to evaluate a person’s mental health. 

The assessment consists of nine questions, each corresponding to the core diagnostic criteria for major depressive disorder (MDD). The questionnaire prompts you to reflect on how often you’ve experienced specific symptoms over the past two weeks. Some symptoms include feeling down, having trouble sleeping, or lacking interest in activities you normally enjoy. 

The PHQ-9 is brief and easy to complete, so it’s frequently used as a first-line screening tool in settings like primary care offices, mental health clinics, and telehealth platforms. It’s also commonly used to monitor treatment progress over time. The structure and scoring allows clinicians to get a snapshot of symptom severity and determine whether  further evaluation or intervention may be needed. 

The History and Development of the PHQ-9

The PHQ-9 was developed by Drs. Robert Spitzer, Janet Williams, Kurt Kroenke, and their colleagues as part of a broader effort to make mental health screening more accessible and practical in primary care settings. Their work led to the creation of the PRIME-MD (Primary Care Evaluation of Mental Disorders), a diagnostic tool designed to help non-psychiatric clinicians identify common mental health conditions more efficiently.

While the full PRIME-MD covered a range of psychiatric disorders, it was time-consuming and required trained interviewers. To address this, the team extracted a shorter, self-administered version focused solely on depression – the PHQ-9. This focused questionnaire preserved the diagnostic accuracy of the original while making it much easier to use during routine medical visits.

What are the PHQ-9 Questions?

The PHQ-9 questionnaire is made up of nine core questions, each one targeting a symptom of depression as defined by the DSM diagnostic criteria. These questions ask how often the individual has experienced specific symptoms over the past two weeks. Responses are scored from 0 to 3, where:

• 0 = Not at all

• 1 = Several days

• 2 = More than half the days

• 3 = Nearly every day

Here’s what each item on the PHQ 9 assessment asks about:

1. Little interest or pleasure in doing things (A sign of anhedonia – a reduced ability to enjoy activities.)

2. Feeling down, depressed, or hopeless (Captures core depressed mood.)

3. Trouble falling or staying asleep, or sleeping too much (Assesses sleep disturbances, common in depression.)

4. Feeling tired or having little energy (Low energy or fatigue is a hallmark symptom.)

5. Poor appetite or overeating (Reflects changes in appetite, either loss or gain.)

6. Feeling bad about yourself – or that you are a failure or have let yourself or your family down (Touches on feelings of guilt, worthlessness, or low self-esteem.)

7. Trouble concentrating on things, such as reading the newspaper or watching television (Evaluates cognitive symptoms like difficulty focusing.)

8. Moving or speaking so slowly that other people could have noticed? Or the opposite – being so fidgety or restless that you have been moving around a lot more than usual (Assesses psychomotor changes, either slowing down or agitation.)

9. Thoughts that you would be better off dead or of hurting yourself in some way (Screens for suicidal thoughts or self-harm risk.)

After the nine symptom-related questions, the PHQ-9 includes an important but unscored item: “If you checked off any problems, how difficult have these problems made it for you to do your work, take care of things at home, or get along with other people?”

This question helps clinicians understand how much the symptoms are interfering with the person's daily life – an important factor in determining the need for treatment. These questions not only help screen for depression but also provide insight into the severity and impact of the symptoms.

How the PHQ-9 Scoring System Works

To calculate the PHQ-9 score, you add up the points (0-3) assigned to all nine questions. This gives you a total score between 0 and 27, which helps determine the severity of depressive symptoms. 

Here’s a general guide to PHQ-9 scoring and how to interpret the results:

This PHQ-9 scoring system is widely used in clinical settings to help guide treatment decisions, such as whether to initiate therapy, monitor symptoms over time, or refer to a mental health specialist. It’s also helpful in tracking progress during treatment, as changes in a person’s PHQ-9 score can reflect how well they’re responding to care. 

Keep in mind that while the PHQ-9 scoring system is a useful tool, it’s just one part of a comprehensive mental health assessment. A high or low score should always be interpreted in context by a healthcare provider.

PHQ-9 Scoring Interpretation

While the PHQ-9 score provides a helpful snapshot of depression severity, it’s not meant to be used in isolation. Clinicians interpret scores in the context of a patient’s overall health, history, and current circumstances. A high score may raise concern, but it doesn’t automatically confirm a diagnosis of depression.

For example, someone who recently experienced a major life stressor – like job loss or a death in the family – might temporarily score high without having a long-term mental health condition. On the other hand, a lower score doesn’t always rule out the need for support, especially if someone is struggling with daily functioning or has a history of depression.

Here’s how scoring interpretation typically informs next steps:

• Scores of 0-4 (minimal or no depression): Usually no treatment is needed. Clinicians may simply monitor symptoms over time.

• Scores of 5-9 (mild depression): May warrant watchful waiting, supportive counseling, or self-help strategies. Clinician might encourage follow-up to see if symptoms improve.

• Scores of 10-14 (moderate depression): Often suggests the need for further evaluation. Treatment may include therapy, lifestyle changes, or in some cases, medication.

• Scores of 15-19 (moderately severe depression): Typically calls for active treatment, such as psychotherapy and possibly antidepressant medication. Ongoing monitoring is important.

• Scores of 20-27 (severe depression): Strongly indicates the need for immediate clinical attention. Referral to a mental health specialist and a more intensive treatment plan are often recommended.

Additionally, responses to the final, unscored question about functional impairment play a key role in decision-making. Even a moderate PHQ-9 score combined with significant life disruption may prompt earlier intervention.

PHQ-9 Limitations and Considerations

While the PHQ-9 is a valuable screening tool, it’s not a standalone diagnostic instrument. Because it relies on self-reporting, results can be influenced by personal bias, misunderstanding of questions, or difficulty in accurately assessing one's own symptoms.

It should never replace a full mental health evaluation by a qualified provider. If your score raises concerns, it’s important to follow up with a healthcare professional who can provide a more complete assessment and recommend appropriate care.

How to Access and Use the PHQ-9

The PHQ-9 test is widely accessible and often used as part of routine health checkups. Many patients first encounter it during a visit to their primary care provider, where it may be included in intake forms or wellness screenings. It's also frequently used by therapists, psychiatrists, and nurse practitioners as part of a mental health assessment.

With the rise of telehealth, the questionnaire is now commonly available through online mental health platforms, virtual care services, and digital intake forms. Many wellness and therapy apps also include the PHQ-9 assessment as a free screening tool to help users monitor their mood over time.

In most cases, it's free to use and often built into patient portals, making it a convenient first step for anyone concerned about their mental health.

How Can LifeMD Help?

If you're looking for support with depression or want to learn more about potential treatment options, LifeMD may be able to help. LifeMD is here to support your mental health with personalized, judgment-free care. The LifeMD Mental Health Program offers flexible virtual treatment tailored to your needs, whether you’re navigating everyday stress, social anxiety, or symptoms of depression. Your provider may recommend prescription medication taken daily or only as needed — all included in your monthly membership.

Get started today by completing a brief intake form.

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