Source: Kroenke et al., 2001 (PubMed).
The Patient Health Questionnaire 9-item (PHQ-9) is a widely used nine-item questionnaire for reflecting on mood and interest. Developed by Kroenke, Spitzer, and Williams in 2001, it asks about feelings over the past two weeks on a 4-point frequency scale (0 = Not at all, 1 = Several days, 2 = More than half the days, 3 = Nearly every day). The total score ranges from 0 to 27.
How It Works:
Each item measures how often a feeling showed up recently. Adding the scores gives a single number you can watch over time. Higher numbers mean the feelings were more frequent, not that anything is "wrong" with you.
A Note on the Score:
Researchers often group totals as a rough guide: 0-4 rare, 5-9 occasional, 10-14 more often, 15-19 persistent, 20-27 frequent. These bands describe frequency only; they are not labels for any condition.
Why People Use It:
Many clinics and researchers use the PHQ-9 to track mood over time, and many people use it privately to notice patterns in their own low mood. It is a self-reflection aid, not a clinical evaluation.
Important Note:
This self-check is for personal emotional reference only. It does not constitute medical advice, diagnosis, or treatment. Please consult a licensed mental health professional for any clinical question.
Related Resources:
If low mood is on your mind, our GAD-7 Anxiety Test can help you reflect on worry too. If you ever feel you need to talk to someone, visit our Mental Health Help (US) page for confidential support lines.