Perseverative Thinking about Suicide Questionnaire (PTSQ): Validation of a new measure to assess suicide-specific rumination

Background: Suicide-specific rumination has been shown to be associated with lifetime suicide attempts as well as suicide intent and might be an important risk factor for the transition from suicidal ideation to suicidal behavior. Based on this background, the wording of the items of an often-used self-report measure assessing core characteristics of rumination was adapted to assess specifically suicide-specific rumination. Methods: The entire study sample comprised N = 1689 participants from the German healthcare sector. A total of 721 participants with a history of suicidal ideation (68% female; Mage = 30.63, SDage = 8.41, range: 18–81 years) who had completed five measures assessing suicide-specific rumination, suicidal ideation, depression, hopelessness, and resilience were included for the present examination. Factorial validity (Exploratory [EFA] to determine the appropriate number of factors and confirmatory factor analyses [CFA] after randomly splitting of the sample to validate the EFA solution), construct validity, and reliability were evaluated. Results: The EFA revealed a one-factor solution consisting of four items, which could be confirmed within a CFA (RMSR = 0.006; RMSEA = 0.039; CFI = 0.999; TLI = 0.998). Internal consistency was excellent with Cronbachs α = 0.93. Construct validity was given with moderate to high positive correlations with suicidal ideation (0.76), depression (0.55), and hopelessness (0.38) and negative correlation with resilience (−0.31). Participants with recent suicidal ideation and/or lifetime suicide attempt reported significantly more suicide-specific rumination than those with only lifetime suicidal ideation. Conclusion: A new 4-item measure for suicide-specific rumination was developed and could be shown to be a reliable and valid instrument in a large German sample. Results emphasize the potential importance of suicide-specific rumination for the understanding of trajectories of suicidal ideation and suicide risk assessments.