Who Gets by with Help from Friends? Multilevel Associations Between Loneliness, Friend Support, and Emotion Regulation in Adolescents with and Without Self-Injury.

Adolescence is a life period marked by increased emotionality, and, for some, volatile friendships and emotion dysregulation. Yet little research has examined peer processes in relation to adolescent emotion dysregulation from a dynamic perspective. This 3-wave longitudinal study examined two peer-related processes - loneliness and friend support - in association with emotion dysregulation with data collected during the COVID-19 pandemic. Further, we examined if these associations differed in those who had histories of non-suicidal self-injury (NSSI), a behavior known to be associated with emotion dysregulation. The sample included U.S. adolescents assigned female at birth (N=91; M age= 15.92) who were oversampled for a history of NSSI (62%). Results from multilevel regression models indicated that loneliness and emotion dysregulation were positively associated, both on average across timepoints (between-person) and in terms of deviations from adolescents' average levels of loneliness at each timepoint (within-person). At the within-person level, friend support and emotion dysregulation were negatively associated. At the between-person level, higher average levels of friend support were only associated with less emotion dysregulation in adolescents with no history of NSSI. When both processes were included in the model, loneliness remained significantly associated with emotion dysregulation. Results indicate that feeling lonely is strongly related to emotion dysregulation in adolescent females. The lack of negative association between emotion dysregulation and support from friends in adolescents with NSSI underscores the need for additional clinical attention for this group of youth to better understand interpersonal risk and protective processes.