Locus of control and the long-term effects of parental smoking on mental health☆

Rationale: Few studies take a life course perspective to explain if exposure to second-hand smoke in childhood influences mental health in adulthood. Importantly, no study provides empirical evidence on the pathways through which exposure to second-hand smoke in childhood influences mental health in adulthood. There is also limited evidence on the factors that moderate the relationship between second-hand smoke exposure and mental health. To inform policy, it is important to explore the pathways through which second-hand smoke influences mental health and understand factors that are likely to moderate this relationship. Objectives: The objective of this paper is to examine if exposure to parental smoking in childhood influences mental health in adulthood. The study examines general health and smoking status in later life as potential channels and if locus of control (LoC), a personality trait developed in childhood and adolescence, moderates the relationship between exposure to parental smoking in childhood and mental health in adulthood. Methods: Using 21 waves of longitudinal data from the Household, Income and Labour Dynamics in Australia (HILDA), the study conducts regression analyses that adjust for the potential effects of confounders and other biases. Results: The results show that exposure to parental smoking in childhood is associated with a decline in mental health in later life, and that general health status and smoking status in adulthood are channels through which exposure to parental smoking in childhood influences mental health in adulthood. Specifically, those who are exposed to parental smoking in childhood tend to have poorer general health and a higher probability of being smokers in adulthood, both of which negatively impact mental health. The findings point to the moderating role of LoC, such that being more internal on LoC dampens the negative effects of exposure to parental smoking on mental health. Conclusion: The findings from this study lend support to the need to address the long-term implications of behaviours that are harmful to health. The findings also suggest that LoC has implications for an individual's psychological resilience against the negative effects from exposure to parental smoking in childhood.