BACKGROUND: Recently there has been a growing body of research examining Borderline Personality Disorder in youth, i.e., childhood and adolescence (Hawes, 2014). Nevertheless, diagnosis in this age group remains controversial, partly due to concerns regarding the validity of the construct (Griffiths, 2011). Predictive validity reflects the degree to which BPD in youth is prognostic of future impairment, and is considered a crucial aspect of the validity of a construct (Van Os et al., 2009). While, a small body of literature has considered the stability of BPD symptoms over time, there are few studies that have examined the long-term clinical and psychosocial impacts of the disorder. The few studies that have reported negative outcomes in youth with BPD symptoms in community populations (e.g., Cohen et al., 2007; Winograd et al., 2008) utilised ad hoc, self-created assessments of BPD rather than established, validated tools. Furthermore, these studies did not consider the mechanistic pathways from early BPD symptoms to outcomes in late adolescence/early adulthood (e.g., do BPD symptoms increase risk of bullying exposure, subsequently heightening risk of depression symptoms?).

AIMS: To explore to what extent BPD symptoms at 11-12 years of age are predictive of future psychopathology and negative psychosocial outcomes, and to examine mechanisms via which increased risk manifests.