Anatomical location of non-suicidal self-injury: A latent class analysis of functional, cognitive, and behavioural profiles of people who self-injure

BACKGROUND: Anatomical location is a core yet commonly overlooked characteristic of non-suicidal self-injury (NSSI). Despite intuitive assumptions that the location of NSSI conveys clinically meaningful information, empirical evidence in this area remains limited. As such, we adopted a novel approach to categorising the anatomical location of NSSI by visibility. We grounded our investigation within established models of NSSI to understand the functional, cognitive, and behavioural characteristics associated with one's anatomical choices. METHOD: 1103 participants with a lifetime history of NSSI (Mage = 24.5, 83.4% female) completed an online self-report questionnaire. We analysed data using latent class analyses, followed by post hoc ANOVAs and chi-square tests. RESULTS: We identified three latent classes, reflecting distinct patterns of anatomical location and visibility of NSSI. The class with the most concealed NSSI (32.6%) showed the greatest endorsement of intrapersonal functions and expectancies. The class with the most visible NSSI (20.2%) was not associated with stronger endorsements of interpersonal functions, but was instead associated with greater NSSI frequency, broader bodily involvement, and stronger anti-suicide functions. The final class represented an intermediate group (47.2%), with probabilities of NSSI and visibility falling between those in Classes 1 and 2. DISCUSSION: Our findings advance the understanding of NSSI location and provide a theoretically meaningful conceptualisation of anatomical location by outlining key differences across various functions, expectancies, frequency, and form of NSSI. These insights expand on models of NSSI to support the clinical and theoretical relevance of anatomical location. Together, our study offers important implications for the assessment and intervention of NSSI.