Family environment in adolescence predicts wellbeing in young adulthood: A test of longitudinal ventral striatal activity as a differential susceptibility factor for developmental outcomes

Prior studies demonstrated heightened ventral striatal (VS) activity in response to reward in adolescence, but little is known about how reward sensitivity interacts with parent attachment to predict outcomes in young adulthood. In this pre-registered, four-wave, functional magnetic resonance imaging (fMRI) study (n = 299 at T1), we examined whether heightened neural and behavioural reward sensitivity across adolescence makes individuals more susceptible to the influence of parent attachment on alcohol use, prosocial behaviour, and wellbeing in young adulthood. Participants played an fMRI gambling task that involved winning or losing money for themselves or a friend yielding a measure of adolescent neural reward sensitivity in VS. Subsequently, data on alcohol use, prosocial behaviour, and wellbeing were collected in young adulthood. Following differential susceptibility theory, we hypothesized for better and worse scenarios for young adults who exhibited higher reward sensitivity as adolescents compared to their peers with lower reward sensitivity. Results showed that avoidant parent-adolescent attachment in adolescence was negatively associated with wellbeing in young adulthood seven years later. We confirmed the adolescent peak in reward sensitivity in the VS, although VS activity did not function as a neurobiological susceptibility marker. Greater VS activity in response to a reward for a friend, however, was associated with less prosociality towards an unknown peer in young adulthood. This suggests that VS activity for close others is an index for ingroup-outgroup differentiation. Together these findings highlight how social experiences and brain development during adolescence may have prolonged impact on socioemotional outcomes later in life.