It's nice to have a friend: How adolescent friendships protect against and contribute to internalizing problems

Adolescents often view friendships as one of the most important relationships in their lives, and this view is supported by research. Theory has suggested that friends can have beneficial effects by providing a sense of belonging and support, buffering against adverse experiences and modelling adaptive behavior. However, they can also have detrimental effects by modelling negative and maladaptive behaviors and by socializing internalizing problems. This dissertation aimed to study how close friends can contribute to increases and decreases in internalizing problems in adolescence. The first aim was to study the protective effects of friendship quality on internalizing problems in both a global risk setting (the COVID-19 pandemic) and a personal one (bullying victimization). I found that adolescents who perceived more friend support reported less internalizing problems during the COVID-19 pandemic and when they were victimized compared to adolescents who reported lower levels of friend support. Next, this dissertation moved beyond mere perceptions of friendship quality toward the behaviors within friendship dyads that may protect against or contribute to internalizing problems. Specifically, the second aim was to study the associations of self-reported co-rumination and observed patterns of problem talk with friendship quality and internalizing problems. I found more evidence for the link of problem-talk behaviors with friendship quality than its link with internalizing problems. Lastly, I examined dyadic effects within friendships to take into account adolescents’ own perceptions as well as their friends’ behaviors and perceptions. The third aim was to study dyadic effects in adolescent friendships: Socialization of depressive symptoms and patterns of friends’ responding behavior during problem talk. I found little to no evidence for dyadic effects: Friends’ depressive symptoms did not predict adolescents’ depressive symptoms, nor was there clear evidence for a link between observed problem-talk with friends and adolescents’ perceived friendship quality or internalizing problems.