The influence of friendships on the mental health of maltreated youth: A pre-registered systematic review using a developmental psychopathology perspective.

Friendships are a potential factor that influence maltreated children's risk for psychopathology. This systematic review examined (1) how friendships influence the association between child maltreatment and psychopathology and (2) developmental differences in how friendships influence this association. Four databases were searched. Inclusion criteria were primary study, quantitative, measures of maltreatment and friendship up to the age of 18 years, measures of psychopathology up to the age of 24 years, and a non-maltreated sample. Exclusion criteria were qualitative, reviews or meta-analyses, no distinction between maltreatment and other trauma, and no differentiation between friendships and other support. Risk of bias was assessed. Data were narratively synthesized. Two hundred thirty-five articles were retrieved for full review. Fourteen met inclusion criteria ( N = 98,676 participants). Eleven of the fourteen studies found that some aspect of friendships influenced the association between maltreatment and psychopathology, with positive qualities generally decreasing risk and negative qualities increasing risk for psychopathology. However, peer support exacerbated maltreated children's risk for psychopathology in two studies. Only three studies assessed friendship prior to adolescence, which precluded conclusions regarding developmental differences. Future research should consider developmental differences and use findings and validated measures from the peer relations literature to better understand how friendships influence maltreated youth's vulnerability to psychopathology.