Factor structure and psychometric properties of the modified scale for suicidal ideation among suicidal youth

Background: Although suicidal behaviors occur at a high rate in adolescence, relatively few interview-based measures are available to assess suicidal ideation among youth. Existing interview measures are limited by a paucity of empirical study, a failure to conform to standard suicide nomenclature, or a lengthy administration time. This study presents data on the psychometric properties and factor structure of the brief, layperson- administered Modified Scale for Suicidal Ideation (MSSI) among suicidal youth. Methods: The MSSI was administered to an inpatient sample of 102 suicidal youth aged 13-17 years. Additional interview and self-report measures were administered to examine the convergent validity of the MSSI. Results: Consistent with previous findings among suicidal adults, the MSSI displayed good internal consistency and expected patterns of convergent validity. Principal component analysis revealed a bidimensional structure, with factors corresponding to (1) Desire and Ideation and (2) Plans and Preparations. Each factor displayed acceptable internal consistency and expected patterns of convergent validity via associations with hopelessness, depressive symptoms, impulsivity, and a self-report measure of suicidal behaviors. The Plans and Preparations factor significantly associated with the presence of a current suicide attempt and with greater suicide intent among attempters, whereas the Desire and Ideation factor did not. Conclusions: The MSSI appears to be a reliable and valid instrument to assess suicidal ideation among distressed youth. Clinicians are encouraged to pay particular attention to responses on the Plans and Preparations factor given its stronger association with suicide attempt and more serious suicide intent.