Warning signs in a period of acute risk for suicide attempt: The utility of count- and combination-based classification

This study sought to establish if models involving the specific combinations of identifiable behavioral warning signs (WS; i.e., alcohol use, suicidal communications, preparation of personal affairs, experiencing negative interpersonal life events) for a suicide attempt outperformed a simpler count model of WS to distinguish an acute risk period (the six hours prior to a suicide attempt) from a control period (a matched six-hour period the day prior). Generalized linear mixed models tested all logical combinations of four behavioral WS in addition to a count variable of the number of behavioral warning signs. For the count variable, receiver operating characteristic curve analysis was utilized to determine the optimal cut point for the number of endorsed WS. Area under the curve (AUC) compared classification across all models, with the count model demonstrating similar classification performance to the best multivariate model (AUCs of 0.72 and 0.73, respectively), with an optimal cut point of endorsing one or more WS. Although determinations of acute risk should be informed by multiple sources of information, this study suggests a relatively simple count-based approach that considers the presence of one (or more) behavioral WS may be used as a potential indication of increased acute risk for suicide attempt.