Generalisability of the interpersonal theory of suicide to latent profiles of young people attending treatment in a suicide prevention service

Objective: The Interpersonal Theory of Suicide (ITS) could help identify differences in groups of suicidal adolescents and inform treatment. Method: Latent Profile Analysis (LPA) using thwarted belongingness (TB), perceived burdensomeness (PB), hopelessness, and capability was conducted on data from an at-risk clinical sample (N = 500). The ITS prediction that changes in TB and PB are associated with changes in suicidal ideation was tested using admission and discharge data. Results: Latent Profile Analysis identified three profiles with increasing complexity and severity on ITS factors. The profiles were labelled low-severity (7.6% of participants), moderate-severity (45.2%), and high-severity (47.2%). ITS predictions were partially supported for the full sample and only for the high-severity and moderate-severity subgroups, whereby changes in TB were significantly associated with changes in suicidal ideation over the course of treatment. However, changes in PB were only significant in the moderate-severity subgroup, and none of the ITS predictions were supported in the low-severity subgroup. Additionally, effect sizes for changes in TB and PB were modest in all analyses. Conclusions: Our findings highlight the importance reducing low belongingness in youth, which is a component of all supported interventions of youth suicide prevention. However, given the modest association of changes in ITS variables had with changes in suicidal ideation, it may be fruitful to elaborate on the relative importance on types of low belongingness or include other non-ITS variables.