The present studies investigated levels of prosocial behaviours from childhood to adolescence, using a multi-informant, cross-cultural perspective. All but one of the developmental trajectories identified were characterised by stable or declining levels of prosocial behaviours. Further research longitudinally investigating prosociality across developmental periods is needed to clarify prosocial behaviour development over time.

Individual differences exist in the association of prosocial behaviour with mental health. While high prosociality tends to co-occur with low levels of mental health problems, high prosociality and internalizing/externalizing problems can co-occur in subgroups of children. Child, mother and family characteristics are predictive of individual differences in prosocial behaviour and mental health development. Mechanisms underlying these associations warrant future investigations.