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 in arthritis. The objectives of this study were 1) to determine the proportion of systemic sclerosis (SSc; scleroderma) patients who responded "yes" to item 9 who endorsed active suicidal ideation in response to more direct questions during a structured clinical interview, and 2) to report whether the PHQ-8, which does not include item 9 from the PHQ-9, performs similarly to the PHQ-9.
Patients were recruited from the Canadian Scleroderma Research Group Registry. The PHQ-9 and Composite International Diagnostic Interview (CIDI) depression module were administered during a phone interview. Scores on the PHQ-8 were calculated by removing item 9 from the PHQ-9. Item 9 responses were compared to suicidal ideation and intent in the last year based on the CIDI. Scores on the PHQ-8 and PHQ-9 were compared using Pearson's correlations.
There were 345 patients interviewed, of whom 31 (9.0%) endorsed item 9 of the PHQ-9. Of those, based on the CIDI, 14 (45.2%) had passive thoughts of suicide or death. Only 1 patient (3.2%) had thoughts about suicide in some detail at any point in the last 12 months. The correlation between PHQ-9 and PHQ-8 scores was 0.998.
Item 9 appears to identify many patients who do not report active suicidal ideation. The PHQ-8 may be a better option for assessment of depressive symptoms than the PHQ-9 in patients with SSc.