Developmental trajectories of same-sex friendship conflict from pre-adolescence to middle adolescence and associations with changes in social-emotional adjustment among Chinese adolescents.

This study investigated adolescent same-sex friendship conflict trajectories and their associations with social-emotional adjustment in a sample of Chinese adolescents (N = 2001, 51.8% boys) from Grades 6 (Wave1, Mage = 12.31 years old, SDage = 0.49) to 10. Using latent class growth analysis, three distinct trajectories of friendship conflict frequency were identified: low-slightly increasing, low-sharply increasing, and high-decreasing-stable. Consistent with an escalation hypothesis, the low-sharply increasing group exhibited a greater increase in depressive symptoms but not interpersonal relationships over time compared to the low-slightly increasing group; the high-decreasing-stable group demonstrated a greater decrease in peer rejection (i.e., "recovery hypothesis") compared to the other two groups, while simultaneously maintaining stable, higher levels of depression and loneliness (i.e., "scar hypothesis"). The findings highlight the developmental heterogeneity in friendship conflict frequency and the importance of understanding the effects of friendship conflict from a dynamic perspective.