Purpose - To explore client-reported functions of deliberate self-injury for prisoners located within a Dangerous and Severe Personality Disorder site. Design/methodology/approach - As interviews produced in depth data indicating a very idiosyncratic experience of the function of deliberate self-injury, Interpretative Phenomenological Analysis was used within a case study design. Findings - Identified functions mirrored current quantitative research but few emerging themes were identified across the sample. Participants presented with varying levels of insight into their deliberate self-injury. Originality/value - A “status-seeking” function of deliberate self-injury was also observed, which is not explicitly discussed within the current literature base. This study’s findings can be of use to treatment providers for this population given their complex responsivity needs. Research limitations – a small sample of young males were used within the study.