The PHQ-9 versus the PHQ-8 - Is item 9 useful for assessing suicide risk in coronary artery disease patients? Data from the Heart and Soul Study

Objective: Item 9 of the Patient Health Questionnaire-9 (PHQ-9), which inquires about both passive thoughts of death and active ideas of self-harm, has been used to assess suicide risk. The objectives of this study were (1) to determine the proportion of patients who responded "yes" to Item 9 who endorsed active suicidal ideation in response to more direct questions from a structured clinical interview and (2) to compare the sensitivity and specificity for detecting cases of depression of the PHQ-9 and the PHQ-8, which does not include Item 9, as well as the correlation between the PHQ-8 and PHQ-9. Methods: Coronary artery disease (CAD) outpatients were administered the PHQ-9 and the Computerized Diagnostic Interview Schedule (C-DIS). Item 9 responses were compared to suicidal ideation and intent in the last year based on the C-DIS. Scores on the PHQ-8 were obtained by eliminating Item 9 from the PHQ-9. Test characteristics of the PHQ-9 and PHQ-8 were compared. Results: Of 1022 patients, 110 (10.8%) endorsed Item 9. Of those, only 22 (19.8%) reported thoughts about committing suicide, and only 9 of those (8.1%) reported a suicide plan any time in the last year based on the C-DIS. Correlation between PHQ-9 and PHQ-8 scores was r. =. 0.997. Sensitivity and specificity for the PHQ-9 (54%, 90%) and PHQ-8 (50%, 91%) to detect major depression were similar. Conclusion: Item 9 does not appear to be an accurate suicide screen. The PHQ-8 may be a better option than the PHQ-9 in CAD patients.