PHQ-9 and Suicide Prevention

The PHQ-9 Depression Questionnaire was found to predict both suicides and suicide attempts among a sample of people being treated for depression as outpatients. This research also revealed that the risk of suicide attempts and suicides “emerged over several days and continued to grow for several months” which confirms “the need for sustained and organized follow-up care.” The authors cautioned that their results could not be used as evidence to justify population-based screenings in non-clinical settings.

The authors also suggested that instruments developed to specifically focus on suicidal ideation as a predictor of suicidal behavior might measure risk more accurately that the PHQ-9 since it  was “designed to measure depression severity rather than identify risk of suicidal behavior”

Among outpatients being treated for depression, a positive response to Question 9, which asks about “thoughts that you would be better off dead or of hurting yourself in some way” predicted both suicide attempts and suicides over the next year despite the differing patterns of risk for these behaviors (e.g. older people, especially men, were more at risk for suicide, younger people were more at risk for attempts). The 13 percent of the sample who reported ideation “nearly every day” or “more than half the days” in the previous two weeks accounted for 53 percent of suicide attempts and 54 percent of suicides in the sample over the year after the questionnaire was administered.

Simon, G. E., Rutter, C. M., Peterson, D., Oliver, M., Whiteside, U., Operskalski, B., & Ludman, E. J. (2013). Does response on the PHQ-9 Depression Questionnaire predict subsequent suicide attempt or suicide death? Psychiatric Services, 64(12), 1195-1202.