Early childhood and early adolescent predictors of internalising symptoms in adolescents: findings from a longitudinal study in a high-risk South African environment

This study investigates predictors of internalising symptoms among adolescents aged 16 to 19 years in a high-risk context in South Africa. Specifically, it explores early childhood (antenatal to 18 months postpartum), and early adolescent (13 to 14 years) predictors of internalising symptoms measured during later adolescence (16-19 years), aiming to identify key factors influencing mental health outcomes in this vulnerable population. Utilising a unique 18-year longitudinal dataset, we included a total of 314 adolescent participants from South Africa in the analysis and employed an adaptive elastic net regularised regression to analyse the effects of 18 predictors from early childhood and early adolescence on internalising symptoms at ages 16 to 19 years. The broadband scale for "internalising" from the Youth Self Report (ages 11-18) was used as the outcome measure. Data collected at five time points across three phases of the longitudinal study were included in the analysis. Key predictors of internalising symptoms were female sex (β=-4.30; 95% CI [-4.42;4.19]). Early childhood predictors with significant associations were maternal depression (β = 1.70; 95% CI [1.56;1.84]) and caregiver employment (β=-0.37; 95% CI [-0.46;-0.29]). In early adolescence, significant predictors included informal house type (β = 0.82; 95% CI [0.71;0.93]), caregiver alcohol use (β = 0.74; 95% CI [0.67;0.81]), exposure to violence (β = 0.73; 95% CI [0.67;0.78]), friend support (β=-0.61; 95% CI [-0.67;-0.55]), food insecurity (β = 0.51; 95% CI [0.46;0.56]), family support (β=-0.33; 95% CI [-0.37;-0.29]), and self-esteem (β=-0.33; 95% CI [-0.37;-0.29]). This study identifies key predictors of internalising symptoms in adolescents from high-risk context, focusing on caregiver variables and social connections. Maternal / Primary cargiver depression and caregiver unemployment in early childhood have lasting effects, highlighting the need for early intervention. In early adolescence, factors such as social environment and caregiver stability are crucial. These insights can inform targeted interventions and policies to support adolescent mental health in high-risk contexts.