Identifying typologies among persons admitted to hospital for non-fatal intentional self-harm in Victoria, Australia.

Purpose: The aim of this study was to determine whether people who have been hospitalised as the result of non-fatal self-harm form meaningful groups based on mechanism of injury, and demographic and mental health-related factors.

Methods: A retrospective analysis of 18,103 hospital admissions for self-harm in Victoria, Australia over the 3-year period 2014/2015-2016/2017 recorded on the Victorian Admitted Episodes Dataset (VAED). The VAED records all hospital admissions in public and private hospitals in Victoria. The primary analysis used a two-step method of cluster analysis. Initial analysis determined two distinct groups, one composed of individuals who had a recorded mental illness diagnosis and one composed of individuals with no recorded mental illness diagnosis. Subsequent cluster analysis identified four subgroups within each of the initial two groups.

Results: Within the diagnosed mental illness subgroups, each subgroup was characterised by a particular mental disorder or a combination of disorders. Within the no diagnosis of mental illness groups, the youngest group was also the most homogenous (all females who self-poisoned), the oldest group had a high proportion of rural/regional residents, the group with the highest proportion of males also had the highest proportion of people who used cutting as the method of self-harm, and the group with the highest proportion of metropolitan residents also had the highest proportion of people who were married.

Conclusions: Preventative interventions need to take into account that those who are admitted to hospital for self-harm are a heterogeneous group.