RESUMEN
OBJECTIVES: The Transdiagnostic Self-injury Interview (TSI) is a new measure that assesses the onset, frequency, methods, and severity of non-suicidal self-injury. The aims were to demonstrate the feasibility of a TSI validation study, and to investigate TSI's criterion validity, clinical correlates, and interrater reliability. MATERIALS AND METHODS: Recruiting sites were psychiatric in- and outpatient units. Feasibility targets included number of participants completing the study, TSI completion time, total participation time, participants experiencing exacerbation of symptoms, along with other targets. Criterion validity was evaluated using the Deliberate Self-Harm Inventory (DSHI). Clinical correlates were examined with the Columbia-Suicide Severity Rating Scale (C-SSRS), the Personal and Social Performance Scale, the Affective Lability Scale-18, and the Brief Trauma Questionnaire. Interrater reliability was evaluated with video recordings and written material. RESULTS: Fifty participants were included. The majority were women (76%) and had a mean age of 31.3 years (SD: 10.4). Schizophrenia (44%) and schizoaffective disorder (18%) were the most prevalent diagnoses. TSI took an average 9.3 min to complete and the total participation time was on average less than one hour. One participant experienced an exacerbation of self-injury ideation (without the need of intervention). A significant correlation was found between TSI and DSHI (r: 0.94, p-value: < 0.001). TSI was correlated to C-SSRS ideation intensity and ideation frequency but not suicidal attempts. TSI was not significantly correlated to other measures. Interrater reliabilities were statistically significant. CONCLUSIONS: The results support the feasibility of a TSI validation study, which is needed to validate TSI in different settings and across diagnoses.