Clinical correlates of suicidality and self-injurious behaviour among Canadian adolescents with bipolar disorder

There is high risk of suicidality in bipolar disorder (BD), particularly in early onset cases. The literature regarding correlates and putative predictors of suicide attempts (SA), non-suicidal self-injury (NSSI) and suicidal ideation (SI) among youth with BD remains sparse. Participants included 197 adolescents with BD, divided into 4 groups: SA (with or without NSSI), NSSI (with or without SI), SI only, and comparison group (CG; no SA/NSSI/SI). Diagnoses, treatment, and suicidality measures were determined via semi-structured interviews, conducted between 2009 and 2017. Univariate analyses were followed by multinomial regression. Overall, 73.6% of participants had history of SA, NSSI, and/or SI. In comparison to CG, SA and NSSI were each associated with BD-II/-NOS (odds ratio [OR] = 15.99, p = 0.002; OR = 16.76, p = 0.003), female sex (OR = 6.89, p = 0.006; OR = 3.76, p = 0.02), and emotion dysregulation (OR = 1.10, p < 0.001; OR = 1.07, p = 0.004). NSSI and SI were each associated with most severe lifetime depression (OR = 1.10, p = 0.01; OR = 1.10, p = 0.01). SA and SI were associated with psychiatric hospitalization (OR = 19.45, p = 0.001; OR = 6.09, p = 0.03). SA was associated with poorer global functioning at most severe episode (OR = 0.88, p = 0.008). NSSI was associated with not living with both natural parents (OR = 0.22, p = 0.009). Study limitations include cross-sectional and retrospective design, stringent cut-offs for SA and NSSI, and recruitment from a tertiary clinical setting. Three quarters of adolescents with BD have had suicidality and/or self-injury. SA and NSSI were most similar to one another, and most different from CG, supporting the broader construct of self-harm. Future research should address the gap in knowledge regarding how sex differences and neurobiology are associated with the observed clinical differences.