Assessment, Ahead of Print.
The interpersonal theory of suicide hypothesizes that suicide ideation (SI) emerges specifically in the context of hopelessness about the immutability of thwarted belongingness (TB) and perceived burdensomeness (PB; i.e., interpersonal hopelessness). The psychometrics of the Interpersonal Hopelessness Scale (IHS), which could be used to test this hypothesis directly, have not been rigorously evaluated. Participants (U.S. adults reporting past-year SI) completed online self-report assessments at Waves 1 (W1; N = 595) and 2 (W2; N = 215), 1 week apart. Confirmatory factor analyses supported a two-factor structure, IHS-TB and IHS-PB. Correlations indicated strong concurrent validity. Hurdle negative binomial regressions indicated that W1 IHS-TB and IHS-PB scores were associated with SI presence and severity at both waves, but this was inconsistent when adjusting for other W1 variables. IHS-TB and IHS-PB demonstrated excellent internal consistency and moderate to good test–retest reliability. The IHS could improve theory testing and suicide risk assessment and management.