Self-injurious behavior in forensic mental health care populations happens frequently and affects not only the individuals involved but also other patients and treatment staff. Moreover, it is linked to violent behavior toward others and is a predictor of suicide. There is still a limited understanding of the underlying functions of self-injurious behavior in forensic patients. This study aimed to enhance this understanding by analyzing 299 incidents of self-injurious behavior recorded between 2008 and 2019 within a gender-mixed Dutch forensic population. The functions of these incidents were categorized by three researchers using the proposed functions of self-injurious behavior identified by Gallagher and Sheldon. Multilevel analyses were conducted to account for repeated incidents per patient and to examine gender and diagnostic differences in functions and severity of self-injurious behavior. The most common function of self-injurious behavior was affect regulation, which was more common among women than among men. Among men, the expression of aggression and control was more common than in women. We recommend that the functions of self-injurious behavior be questioned more directly and specifically to gain a better understanding and to help provide adequate intervention. Further research, particularly qualitative studies, is needed to explore the functions and treatment of self-injurious behavior within forensic populations more deeply.
