Predicting prolonged non-suicidal self-injury behaviour and suicidal ideations in adolescence - the role of personal and environmental factors.

Suicide is one of the leading causes of death among adolescents and repetitional suicidal ideations (SI) and non-suicidal self-injury (NSSI) often precede it. In order to improve recognition of youth who are at high risk of suicide, current study aims to identify which individual variables (personality, self-concept and adverse childhood experiences - ACE) predict prolonged NSSI and SI from middle to late adolescence. A 3-year longitudinal study was conducted with 1101 Croatian adolescents (aged 15-17). 181 students (72.4% females) reported either NSSI or SI or both in T1 and were included in all waves of the study. Analyses are focused on differentiation between adolescents who continue with NSSI/SI and those who stop with it in a 3-year period. Results showed that adolescents with prolonged NSSI/SI had more ACE, especially domestic violence, worse family financial status, higher neuroticism and lower results on self-concept variables. The prediction model of classification of those who have prolonged NSSI or SI was better for SI than NSSI, with predictors explaining 31% of variation in SI. Adolescents who experienced more ACE and report more neuroticism have a higher chance of prolonged SI, while youth who perceive better family financial status and have better relationships with parents have a greater chance to stop with it. For NSSI only neuroticism was a significant predictor. Considering significant variables which could predict prolonged NSSI and/or SI, data presented in this paper have both scientific and practical contribution in understanding, treating and preventing adolescents' mental health problems.