The quadratic relationship between body mass index and suicide ideation: A nonlinear analysis of indirect effects.

A nonlinear indirect effects framework was used to investigate potential interpersonal indirect effects (i.e., perceived burden and thwarted belonging) accounting for the nonlinear relationship between body mass index (BMI) and suicide ideation. Using a sample of 338 undergraduates, results revealed a significant quadratic effect of BMI on suicide ideation via perceived burden only, which became significant as BMI fell below 18.00 kg/m² and above 28.00 kg/m². Our results provide novel information relevant for suicide risk screening in the context of weight- and health-related interventions and provide justification for future longitudinal trials assessing suicide risk across the BMI spectrum.