Testing the interpersonal theory of suicide in adolescents: A multi-wave longitudinal study

Background: Suicide is a major public health crisis among youth. Several prominent theories, including the Interpersonal Theory of Suicide (IPTS), aim to characterize the factors leading from suicide ideation to action. These theories are largely based on findings in adults and require testing and elaboration in adolescents. Methods: Data were examined from high-risk 13-18-year-old adolescents (N = 167) participating in a multi-wave, longitudinal study; 63% of the sample exhibited current suicidal thoughts or recent behaviors (n = 105). The study included a 6-month follow-up period with clinical interviews and self-report measures at each of the four assessments as well as weekly smartphone-based assessments of suicidal thoughts and behaviors. Regression and structural equation models were used to probe hypotheses related to the core tenets of the IPTS. Results; Feelings of perceived burdensomeness were associated with more severe self-reported suicidal ideation (b = 0.58, t(158) = 7.64, p < .001). Similarly, burdensomeness was associated with more frequent ideation based on weekly smartphone ratings (b = 0.11, t(1460) = 3.41, p < .001). Contrary to IPTS hypotheses, neither feelings of thwarted belongingness, nor interactions between burdensomeness and thwarted belongingness were significantly associated with ideation (ps > .05). Only elevated depression severity was associated with greater odds of suicide events (i.e., suicide attempts, psychiatric hospitalizations, and/or emergency department visits for suicide concerns) during the follow-up period (OR = 1.83, t(158) = 2.44, p = .01). No effect of acquired capability was found. Conclusions: Perceptions of burdensomeness to others reflect a critical risk factor for suicidal ideation among high-risk adolescents. Null findings with other IPTS constructs may suggest a need to adopt more developmentally sensitive models or measures of interpersonal and acquired capability risk factors for youth. Refining methods and theoretical models of suicide risk may help improve the identification of high-risk cases and inform clinical intervention.