The Developmental Trajectory of Family Functioning in Junior High School Students: Effects on Preference for Solitude and Social Avoidance

Objectives: Positive family functioning (FF) is critical for adolescent development, yet only a few studies have examined this developmental trajectory pathway. This study aimed to identify different types of FF development trajectories during junior high school students, investigate their influence on social avoidance (SA), and further examine the mediating role of preference for solitude (PS) between them. Methods: A three-wave longitudinal study was used with six-month intervals. Questionnaire data were collected from 436 junior high school students in Jiangxi Province, China. Participants ranged in age from 11 to 14 years old (Mean = 12.89 years, SD = 1.08; 50.2% male). Results: Four heterogeneous types of FF trajectories were identified: (1) a high and increasing group (14.7%); (2) a consistently high group (36.24%); (3) a consistently moderate group (45.86%); and (4) a rapid growth group (3.2%). The developmental trajectories of FF among junior high students significantly varied in their levels of SA (F(3,432) = 32.03, p < 0.001). Compared to the high and increasing groups, the consistently high, consistently medium, and rapid growth groups exhibited higher levels of SA. PS mediated the association between the developmental trajectory of FF and SA. Conclusion: There was a close relationship between the developmental trajectory of FF and SA. Interventions focusing on family system optimization and solitary preference management could effectively mitigate SA behaviors. These findings are important for promoting healthy socialization in adolescents.