The factorial structure of the Suicide Intent Scale: a comparative study in clinical samples from 11 European regions

Abstract

Although the Suicide Intent Scale (SIS) is a widely used instrument in research on suicidal behavior, comparative research on the latent structure of the SIS has been neglected. To determine whether a general factor model of the SIS is supported, alternative factor models of the SIS were evaluated comparatively in 11 clinical samples. The SIS was applied as part of a structured clinical interview to patients after an episode of non-fatal suicidal behavior. The samples were drawn from 11 study centers within the frame of the WHO/EURO multicenter study on suicidal behavior. Three different two-factor and two three-factor models of the SIS were examined in each sample using principal component analysis with orthogonal Procrustes rotation. The factorial structure of the 'subjective part' of the SIS (items 9–14) was strongly supported, whereas an acceptable model fit for the 'objective part' was not found. Possible future revisions of 'objective' SIS items may be worth consideration. As a limitation, the results of the study might not generalize to other samples that use different definitions of non-fatal suicidal behavior.