Abstract
Background: The interpersonal theory of suicide (ITS) may explain the link between alcohol use severity and suicidal ideation (SI) through interpersonal stressors at elevated alcohol use levels. Aims: This study aimed to clarify the indirect effects of perceived burdensomeness (PB) and thwarted belongingness (TB) in this relationship. Method: Cross-sectional data on SI, ITS, and alcohol use severity variables were collected via an online sample (N = 299) screened for lifetime suicidal thoughts or behaviors, nonsuicidal self-injury, and alcohol use. Associations were tested using linear regression with parallel mediators. Results: Alcohol use severity was indirectly linked to SI through the unique indirect effect of PB, and the total indirect effect of both TB and PB. Limitations: Limitations include the cross-sectional design and use of an online sample, which limit causal inferences and generalizability to other high-risk populations. Conclusion: PB and the additive indirect effect of TB and PB may explain the positive relation between alcohol use and SI; implications are discussed.