Comorbid mental disorders in extensively hospitalized patients due to severe self-harm: the association with...

Self-harm is a frequent feature of borderline personality disorder. In severe conditions comorbidity across mental disorders is common. Intellectual developmental disorder (IDD) may be an underlying condition with high frequent self-harming behavior. Based on extensively hospitalized severe self-harm patients, we aimed to 1) explore associations between possible IDD (identified by Hayes Ability Screening Index, HASI), and mental health disorders, and 2) investigate the ability to identify possible IDD with a low-effort HASI subscale. We hypothesized that possible IDD was significantly associated with greater mental health comorbidity.

The study included 42 adults admitted to psychiatric hospitals for severe self-harm. Assessments included diagnostic interviews and IDD screening (HASI) by clinicians, and childhood trauma (patient self-report). Data were analyzed using Poisson regression. Validation of the HASI subscale background information was conducted using ROC analysis and exploratory data analysis.

Possible IDD was significantly associated with higher incidence of mental disorders, even after adjusting for BPD, SUD, autism, and childhood trauma. Possible IDD and childhood trauma were independently associated with the number of mental disorders. The HASI background subscale demonstrated good predictive properties for identifying possible IDD.

Results highlight the importance of assessing IDD among severe self-harm inpatients. A diagnosis of IDD may open the door to a broader range of treatment adaptations specifically addressing the needs of individuals with complex developmental and psychological challenges. Given the small sample size, these findings should be viewed as preliminary and hypothesis-generating. Replication in larger samples is required for further confirmation.