The differential impact of parent and peer-related interpersonal stress on risk for psychopathology: An examination across three timescales

***This is a draft preprint meant to solicit input from the broader scientific community prior to finalization and is thus subject to substantial changes before publication.*** Adolescence is a developmental period, during which peer relationships and interactions become more influential. Existing literature on the effects of relationship quality on mental health outcomes, however, has found that family relationships have robust effects on internalizing symptoms, and peer relationships have an inconsistent impact depending on measures and study design. This has led to a narrative that familial relationships remain the primary interpersonal factor in emerging psychopathology throughout adolescence even though this inferred difference between family and peer environments has never been directly tested. In the present series of three studies, we examined how family and peer relationships separately influence concurrent and prospective internalizing symptoms during adolescence. With a coordinated methodological approach across two independent samples, we utilized multiple types of measurements to analyze the impact these interpersonal domains across complementary timescales (yearly, monthly, and within-day) in two different samples. Study 1 relied on a sample of 169 male and female participants, 8-17 years old, and Studies 2 and 3 relied on a sample of 30 females, who were 15-17 years old. We used linear regression and mixed-effect modeling to examine the comparative between- and within-person effects of family versus peer stress on depression and anxiety, while controlling for other forms of stress. We found that stress from family relationships has consistent between- and within-person effects on internalizing outcomes at all time scales, and often times this leads to family stress being significantly more influential than peer stress. This pattern is not always true, though, as individual difference in episodic (event-based) stress from peers shows a pattern of being more influential on internalizing symptoms than differences in episodic family stress. Subsequently peer environments appear to affect psychopathology more through via episodic stressors like conflicts and arguments than on chronic indicators of status among peers. Finally, unexpected patterns related to whether objective and self-report stress measures were used suggest that within-person effects of episodic interpersonal stress potentially function largely through individuals’ perceptions instead of the objective situation.