Effect of caregiver depression on adolescent internalising and externalising behaviour: findings from a longitudinal study in a high-risk South African environment

Adolescents living in low- and-middle incomeand middle-income countries are at a particular risk of poor mental health. Caregiver mental health plays a crucial role in a child's emotional and behavioural development and may directly impact a child's risk for future development of mental health problems. Data collected as part of a two-decade longitudinal multiphase research project were used. Participants, originally women in their third trimester of pregnancy (n = 449), were recruited from a peri-urban impoverished community outside of Cape Town, South Africa, and assessed at several time-points over subsequent years. Data collected during the three phases of the research were used to assess the effects of early and current caregiver depression on adolescent internalising and externalising behaviour. Analyses of Covariance models were used to explore the effect of caregiver depression on adolescent internalising and externalising behaviour, while controlling for multiple covariates. We analysed data for 313 adolescent participants and their primary caregivers. Caregiver depression patterns had a significant main effect on externalising behaviour, F(3,305) = 4.10 (p = 0.007), but not on internalising behaviour, F(3,305) = 2.71 (p = 0.09). Post-hoc analysis showed that those adolescents exposed to early and current caregiver depression scored on average 3.83 points (95% CI [0.99; 6.66]) higher in externalising behaviour than those exposed to no caregiver depression. Also, adolescents who experienced a change in caregiver, compared to those whose biological mother were still their primary caregiver, reported significantly higher levels of externalising behaviour F(1,305) = 5.10, p = 0.03. The study findings provide crucial insight into critical periods of risk, as well as opportunities for prevention. Preventive interventions should ideally target caregivers and adolescents to prevent or reduce behavioural problems and disrupt intergenerational cycles of mental disorders or behavioural problems.