Examining suicidal thoughts and behaviors across levels of personality functioning: A generalized additive model approach.

Suicide is a leading cause of death among emerging adults in the United States. Despite decades of research attempting to target risk factors, our ability to predict suicide remains insufficient. The objective of our examination was to investigate the utility of Criterion A of the Alternative Model for Personality Disorders in predicting suicide outcomes by identifying the level-specific contribution of levels of personality functioning (LPF) to suicidal thoughts and behaviors. To address our research questions, we employed generalized additive modeling in subsamples of 145 young adults endorsing suicidal ideation, and 158 young adults endorsing at least one lifetime suicide attempt who were recruited from college and clinical settings. Clinical participants endorsed past or current, confirmed or subthreshold borderline personality disorder. Results indicated a nonlinear trend in suicidal ideation with the sharpest increase at Level 2 of the LPF scale, operationalized via the Semistructured Interview for Personality Functioning. In addition, the increase in lifetime attempt history was nonuniform, with the greatest increase in odds ratio ratios occurring between Level 1 and Level 2. Findings support Level 2 of LPF as a potential inflection point for suicide risk detection and further challenge the notion of linear relationships between personality pathology severity and suicide risk. Implications of these findings are discussed. (PsycInfo Database Record (c) 2026 APA, all rights reserved).