The interpersonal theory of suicide posits that thwarted belongingness (TB) and perceived burdensomeness (PB) increase suicide ideation; however, studies have found mixed results regarding this hypothesis among psychiatric inpatients. This study aimed to (a) demonstrate how assessing TB and PB using the Interpersonal Needs Questionnaire (INQ) can provide clinically useful information and (b) investigate how statistical methodology may impact the clinical application of the INQ. Participants were 139 (Sample 1) and 104 (Sample 2) psychiatric inpatients. In both samples, ordinal logistic regression results indicated TB and PB, separately, were significant predictors of suicide ideation-related outcomes; however, when examined as simultaneous predictors, TB was no longer a significant predictor. The interaction between TB and PB was not significant for either sample. Despite this, TB and PB scores provided clinically relevant information about suicide ideation-related outcomes. For example, the highest scores on TB and PB indicated a 93% and 95% chance of having some level of distress due to suicide ideation (Sample 1), a 91% and 92% chance of having some level of desire for death, and a 79% and 84% chance of having some level of desire for suicide, respectively (Sample 2). This study also proposes clinical cutoff scores for the INQ (for TB and PB, respectively, cutoff scores were 22 and 17 for distress due to suicide ideation, 33 and 17 for desire for death, and 31 and 22 for desire for suicide). Although these results indicate that multicollinearity between TB and PB may create interpretational ambiguity for clinicians, TB and PB may each be useful separate predictors of suicide ideation-related outcomes in psychiatric inpatient settings and should be incorporated into suicide risk assessment. Key Practitioner Message: The 15-item Interpersonal Needs Questionnaire (an assessment of thwarted belongingness and perceived burdensomeness) should be incorporated into suicide risk assessment. Among psychiatric inpatients, greater thwarted belongingness and perceived burdensomeness, as separate predictors, were associated with increased levels of distress due to suicide ideation, desire for death, and desire for suicide. The highest scores on thwarted belongingness and perceived burdensomeness indicated a 79% to 95% chance of experiencing an elevated level of distress due to suicide ideation, desire for death, or desire for suicide. Recommended clinical cutoff scores were provided. For example, thwarted belongingness cutoff score of 31 and perceived burdensomeness cutoff score of 22 maximized the sensitivity and specificity of the INQ to detect some level of desire for suicide.
- Death ideation
- Interpersonal needs questionnaire
- Interpersonal theory of suicide
- Suicide ideation
- Thwarted belongingness
- perceived burdensomeness