The dynamic interplay between mental health difficulties and the family environment in early adolescence.

Background: Adolescents experiencing mental health problems have an elevated risk of persisting difficulties as they transition into adulthood, stressing the importance of identifying modifiable factors impacting mental health during adolescence. The family environment is recognised as a key influence on adolescent mental health in theory and interventions. Notably, few studies have disentangled within-person and between-person effects in relating adolescent mental health and the family environment. Methods: We analysed data from 1067 adolescents across three waves using panel graphical vector autoregressive modelling, separating contemporaneous and temporal within-person and between-person associations in relationships between mental health difficulties (i.e., emotional, hyperactivity/inattention, conduct problems) and family-related factors (i.e., aspects of the general family environment, parent-child relationships, and sibling dynamics). We also assessed how the different mental health difficulties and family environment factors were themselves interrelated over time. The mean age (in years) was 10.51 at Wave 1, 12.49 at Wave 2, and 14.49 at Wave 3. Results: Emotional symptoms predicted increases in hyperactivity/inattention and more sibling problems over time. Lack of family support and negative feelings towards family were reciprocally related, indicative of a reinforcing loop. Both mental health difficulties and family environment factors exhibited considerable stability. In contemporaneous within-person associations, mental health difficulties were strongly interrelated, as were aspects of the family environment. Furthermore, conduct problems were linked to externalising behaviours (e.g., fighting with parents, bothering siblings) and emotional symptoms to internalising experiences of family dynamics (e.g., feeling negative towards family, being bothered by siblings). Negative feelings towards family and hyperactivity/inattention were strongly predicted by included variables, while emotional symptoms, fighting with parents, and lacking family support were predictive of other variables. Conclusions: Our findings point to the importance of emotional problems in adolescence, which may contribute to worsened hyperactivity/inattention and more problems with siblings over time, and the interrelatedness of mental health and the family environment. Alleviating internalising problems in affected adolescents may help mitigate development of other mental health difficulties and negative sibling dynamics.