Personal Health Questionnaire Depression Scale – PHQ-9
A self-report tool used to screen, diagnose, monitor, and measure the severity of depression.
Scale Development & Technical Details
Scale Overview
The Personal Health Questionnaire Depression Scale – PHQ-9 was developed by Robert L. Spitzer, Janet B.W. Williams, Kurt Kroenke (1999). It is designed to measure Depression Severity. The scale is intended for use with Adults.
Scale Structure
This instrument consists of 9 items.
Response Format
Respondents rate each item using a custom response format.
Response anchors: 0 = Not at all, 1 = Several days, 2 = More than half the days, 3 = Nearly every day.
Scoring
Items are summed to produce a total score.
Total scores range from 0 to 27. Interpretation guidelines:
- Minimal depression: 0 – 4
- Mild depression: 5 – 9
- Moderate depression: 10 – 14
- Moderately severe depression: 15 – 19
- Severe depression: 20 – 27
Psychometric Properties
Internal Consistency: The scale has demonstrated good to excellent internal consistency with reported Cronbach’s alpha values of 0.88.
Administration
The scale is self-administered and typically takes approximately 3 minutes to complete. It can be administered individually or in group settings. No special training is required for administration.