Elevated Negative Affectivity and Psychoticism in individuals with active Nonsuicidal Self-Injury (NSSI) compared...

Non-suicidal self-injury (NSSI) is a transdiagnostic symptom associated with substantial clinical burden and increased risk of suicidal behavior. Although NSSI occurs across a wide range of psychiatric disorders, research has consistently linked it to maladaptive personality traits. However, most studies have compared individuals with NSSI to healthy controls, limiting our understanding of which personality traits are specifically associated with NSSI. The inclusion of clinical control groups may therefore help clarify which personality traits are associated with NSSI rather than with psychopathology more broadly. This study aimed to investigate whether individuals with psychiatric disorders and active NSSI differ in personality traits, as assessed with the Personality Inventory for DSM-5 (PID-5), compared to those with prior but no active NSSI and those without a history of NSSI.

231 individuals at a psychiatric outpatient unit completed the PID-5 and the Inventory of Statements About Self-injury and were assessed with regards to demographic information, psychiatric illness and previous suicide attempts. Symptom levels of depression and anxiety were measured. Participants were divided into groups of active NSSI (≥ 5 episodes in the past 12 months; n = 123), previous NSSI (≥ 5 episodes, but none in the past 12 months; n = 68) and no previous history of NSSI (n = 40).

Participants with active NSSI scored significantly higher in negative affectivity (F(2, 224) = 10.33, p < .001, η_p² = 0.08) and psychoticism (F(2, 224) = 8.91, p < .001, ηp² = 0.07), compared to those with a previous history of NSSI and those with no previous history of NSSI. The analyses were adjusted for age, sex assigned at birth and symptoms of depression and anxiety.

Active NSSI seems to be associated with increased traits of negative affectivity and psychoticism. This study contributes with new knowledge regarding NSSI and personality traits, which may guide future research on mechanisms, etiology, and treatment approaches.

The study was registered on Clinical Trials: NCT04905797, registration date April 29, 2021.