Assessment of the association between non-suicidal self-injury disorder and suicidal behaviour disorder in females with conduct disorder

BACKGROUND: Non-suicidal self-injury (NSSI) and aggression have been demonstrated to serve as risk factors of suicidal behaviours (SB). Non-suicidal self-injury disorder (NSSID) and Suicidal Behaviour Disorder (SBD) are among new diagnostic categories for further studies in the DSM-5 classification. METHODS: We recruited 196 girls (aged 15.5 ± 1.2 years) diagnosed with conduct disorder (CD). All of them were assessed with respect of non-suicidal self-injury acts, suicidal attempts, psychopathology, self-esteem and general functioning. RESULTS: Age of NSSI onset was significantly lower compared to age of first suicidal attempt. SBD was present in 50.0% of patients with NSSID and the prevalence of NSSID in individuals with SBD was estimated at 52.2%. A diagnosis of NSSID, with at least 8 days of engagement in self-injuries during the preceding year, significantly predicted the risk of SBD. This effect appeared to be independent of depressive symptomatology. LIMITATIONS: Our results cannot be generalized over the whole population of individuals diagnosed with CD because of a lack of male patients, as well as individuals with the most severe and mildest forms of CD. Causal inferences cannot be established due to a cross-sectional study design. CONCLUSIONS: The NSSID with at least 8 days of engagement in self-injuries during the preceding year serves as a predictor of SBD independently of the effects of depressive symptoms. Longitudinal studies are required to confirm our findings. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-021-03168-4.