Abstract
Mothers and adolescent children in Mexican immigrant families may encounter various sociocultural stressors, which may spill over into family interactions and impede each other's internalizing symptoms based on the Family Systems Theory. Empirical evidence is needed to identify the sensitive developmental age when mothers and adolescents are most vulnerable to each other's stressors, addressing gaps in understanding which types of sociocultural stress can spill over and when these spillover effects peak during adolescence. This study adopted a five-year, three-wave dataset that included 604 adolescents (M(Wave1_age)(SD) = 12.92(0.92); 54% female) and 595 mothers (M(Wave1_age)(SD) = 38.89(5.74)) among Mexican immigrant families. Time-varying-effect models showed that the association between maternal stress experiences (cultural misfit, foreigner stress, difficulty paying bills) and adolescent internalizing symptoms was weak to nonsignificant during most of the adolescence period, yet adolescents' sociocultural stress more strongly influenced maternal symptoms, particularly in early adolescence. These findings underscore the profound impact of adolescents' sociocultural stress on maternal mental health and highlight the need to consider youth developmental timing when examining such impact.