Measures Registry

Patient Health Questionnaire-9 (PHQ-9)

Description

The Patient Health Questionnaire-9 (PHQ-9) is a 9-item measure given to patients in a primary care setting to screen for the presence and severity of depression. This measure comes from the larger Patient Health Questionnaire and measures the frequency of depressed mood and anhedonia over the past two weeks.

Purpose

To not only detect but also assess the severity of clinical depression.

Population

Adults

Year of Publication

2001

Reference

Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613. https://doi.org/10.1046/j.1525-1497.2001.016009606.x

Number of Items

Scale Types (Likert=Likert Type; MC=Multiple Choice; T/F=True/False; OR=Open Response)

Likert Type

Likert: 0 = Not at all, 1 = Several days, 2 = More than half the days, 3 = Nearly every day

Subscales

PHQ-2 PHQ-4

Scoring

Scores across the nine items are summed, with total scores ranging from 0-27. Major depression is diagnosed if the patient rates 5 or more of the 9 items a score of 2 or higher and 1 of the items is depressed mood or anhedonia. Other depression is diagnosed if the patient rates 2-4 of the 9 items a score of 2 or higher and 1 of the items is depressed mood or anhedonia. If the patient rates the item "thoughts that you would be better off dead or about hurting yourself in some way" as 1 or higher, this item is counted towards diagnosis regardless of its duration (i.e., score).

Administration

Self-Administered or Interviewer-Administered

Readability/ Literacy Level

N/A

Languages

English

Reliability

N/A

Validity

The sensitivity, specificity, and likelihood ratios for each cutpoint score are provided in Table 3 of the source article. Examination of these values demonstrated a strong association between increasing PHQ-9 scores and the likelihood of major depression.

Construct validity was measured by assessing the association between the PHQ-9 and similar scales, with specific results provided in Table 4 of the source article. These results demonstrated a strong association between the PHQ-9 and all six SF-20 scales.

Limitations

The authors of the source article note that longitudinal studies are needed to further assess the effectiveness of the PHQ-9 and that different methods of measure administration (e.g., via telephone vs. face-to-face) should be studied.

Availability

Publicly Available

Cost

Free

Other Considerations

N/A