Identifying environmental risk factors for childhood and adolescence internalising disorders

The literature reveals a number of environmental risk factors that may contribute to the development of child internalising problems. However, the findings of these studies are usually based on cross-sectional designs, which presents methodological challenges and may not provide adequate grounds for drawing causal conclusions. The identification of causal risk factors is of great importance to the success of intervention and prevention programs. Therefore, it is necessary to investigate the environmental risk factors using sophisticated methods. The purpose of this thesis is to examine environmental risk factors associated with internalising problems in children using the best available methods that will contribute to establishing causal inference.
A systematic review was conducted for the initial study (Chapter 2), with a focus on studies using causally informative study designs to examine environmental risk factors associated with child internalising problems. The study identified several environmental risk factors for children and adolescents' internalising problems, with parental mental health problems emerging as a prominent factor. In the second study (Chapter 3), the relationship between parental mental health (distress) and child internalising problems was explored, using the random intercept cross-lagged panel model, a sophisticated methods that contributes to causal inference. These relationships were examined on the basis of the Family Stress Model, which suggests that low family income affects parent distress, which, in turn, affects child outcomes. The results showed that parental distress did not mediate the relationship between family income and child mental health problems, emphasizing the necessity for additional exploration of this relationship from different perspectives. Thus, the last study (Chapter 4) explored the relationship between parent and child mental health, examining the moderating effect of poverty. Utilizing another causally informative study design, autoregressive latent trajectory models with structured residuals, results revealed that no differences between poverty groups at either the between or within-family levels.
These studies shed light on how environmental risk factors, particularly parental distress, are associated with internalising problems in children/adolescents from a causal perspective. It was highlighted the need to further research into environmental risk factors using sophisticated methods in order to better understand their impact on child internalising problems.