Kristine Marceau

GPA grade point average MCAR missing complete at random RCP Revised Class Play VIF variance inflation factor Child and early adolescent friendships are often unstable (e.g., Meter & Card, 2016). The proportion of Canadian elementary and middle-school students' friendships that were maintained over a 3-month interval ranged from 55% to 63% (Ellis & Zarbatany, 2007).

1 INTRODUCTION Externalising behaviours (e.g., oppositional behaviour, aggression and attention problems) generally peak in toddlerhood (Alink et al., 2006), but if they persist past kindergarten can indicate increased risk for longer-term problems (Alink et al., 2006; Olson et al., 2017), including poor educational achievement, delinquency and adolescent substance use (Farrington, 1989; Masten et al., 2005).

Abstract Objectives: Objectives were to explore: 1) the association between sub-groups with different multi-type childhood maltreatment exposures and depressive symptoms in late adulthood, and 2) the mediating effects of dysregulated physiological stress system function and perceived stress in midlife on the aforementioned associations. Methods: Data come from the Biomarker project (n = 1,053) of the Midlife Development in the United States study.