Patient Health Questionnaire - 9 (PHQ-9)
What is it?
The PHQ-9 is a widely used questionnaire designed to help identify symptoms of depression. It’s based on the criteria for Major Depressive Disorder found in the DSM (Diagnostic and Statistical Manual of Mental Disorders). The PHQ-9 is a simple, self-report tool that asks people to reflect on how they’ve been feeling over the past two weeks. It’s commonly used in healthcare settings to get a quick snapshot of a person’s mental health, making it easier to open up conversations about mood and well-being.
How is it used?
The PHQ-9 is suitable for both adolescents and adults. It takes only about two to three minutes to complete, making it a quick and practical tool in busy clinical environments. The questionnaire asks people to consider how frequently they’ve experienced certain feelings or behaviors over the past two weeks, such as feeling down, having trouble sleeping, or losing interest in activities. Because it’s easy to administer, it’s not only helpful for initial screenings but also for monitoring changes in a person’s mood throughout treatment.
What do the scores mean?
The PHQ-9 consists of nine questions, with each one rated on a scale from 0 (not at all) to 3 (nearly every day). Once the answers are added up, you get a total score that ranges from 0 to 27. Higher scores indicate more severe symptoms of depression, with scores falling into these categories:
0 to 4: This range suggests minimal to no symptoms of depression.
5 to 9: Scores in this range indicate mild depression. The symptoms might not be severe, but it’s worth keeping an eye on.
10 to 14: A score in this range points to moderate depression, which could benefit from some therapeutic support or intervention.
15 to 19: This indicates moderately severe depression, where more focused treatment is likely needed to address the symptoms.
20 to 27: A score in this range suggests severe depression, indicating that immediate clinical attention may be necessary.
A score of 10 or above is generally considered a threshold for identifying depression that might require treatment, whether that’s therapy, medication, or a combination of approaches.
What does the research say?
The PHQ-9 is backed by extensive research, showing that it’s both reliable and valid. When we say it’s reliable, we mean that it consistently produces similar results if a person’s mood hasn’t changed. It’s also valid, meaning it accurately identifies depression symptoms and their severity. Studies have shown that the PHQ-9 has high sensitivity and specificity, which means it’s effective at identifying people who are struggling with depression while minimizing false positives.
In addition to its use as a screening tool, the PHQ-9 is incredibly helpful for tracking progress over time. Clinicians often use it to see how their patients are responding to treatment, making adjustments as needed to better support their mental health.
Developer:
Kroenke K, Spitzer RL & Williams JBW (2001). The PHQ‐9. Journal of general internal medicine, 16(9), 606-613