The dimensionality of suicidal ideation and its clinical implications.

OBJECTIVES: No consensus has been reached regarding the theoretical dimensions underlying the Scale for Suicide Ideation (SSI) and Beck's Scale for Suicide Ideation (BSI), widely used in research and clinical practice. This undermines the understanding and management of suicidal behavior. METHODS: The factor structure of the SSI and the BSI was investigated in 201 patients visiting the emergency department of the Geneva University Hospital, Switzerland, for suicidal ideation or a suicide attempt. RESULTS: Exploratory factor analyses (EFAs) identified a unique theoretical dimension. Item removal based on analyses of communalities improved the explained part of variance in both scales. A joint factor analysis provided results very similar to those yielded by initial EFAs. CONCLUSIONS: The single factor underlying the SSI and the BSI was composed of items encompassing a construct of suicide desire. Nonretained items corresponded to other elements of suicidal behavior (e.g., plans and preparations regarding the upcoming suicide attempt). These scales could not discriminate between suicide ideators and suicide attempters.