Abstract

Offspring of parents with affective disorders (OAD) are at risk of developing a wide range of mental disorders. Deficits in the rearing environment and exposure to adverse events are well known risk factors for negative outcomes in OAD. Building on prior research, this thesis aimed to examine the longitudinal relationships between familial dysfunction, exposure to adverse events, emotional and behavioural well-being, and mental health service utilization in OAD and control offspring of parents with no affective disorder. Studies 1 and 2 in the thesis used data from the TRacking Adolescents’ Individual Lives Survey, a longitudinal study of youth in the Netherlands. 2230 participants (51% female, Mage= 11.1 years, SD = 0.6, at baseline) and their parents completed questionnaires across 6 time points, spanning 15 years. Mental health and behavioural data were measured using standardized questionnaires, while adverse life events and health service utilization were assessed using structured interviews. In the first study, multi- group structured equation modelling revealed that family dysfunction was linked to internalizing and externalizing problems in the OAD (B = 0.05, SD = 0.02, p = .008), but not in controls (B = 0.06, SD = 0.01, p = .636), and that this relationship was stable from middle childhood to adulthood. In the second study, we expanded the scope of investigation from family functioning to cumulative environmental risk, referring to the assessment of multiple risk factors in families, and mental health service utilization. Results from moderated mediation analyses revealed that the OAD were more likely to seek out more intensive mental health services as adults than controls (CI = [0.01, 0.15]), as a function of their cumulative environmental risk and subsequent significant mental health need. Study 3 examined whether a preventative intervention to improve family functioning in OAD might improve offspring’s internalizing and externalizing symptoms through changes in parenting stress. In this study, we compared the offspring of a parent having bipolar disorder (OBD), who underwent the Reducing Unwanted Stress in the Home (RUSH) intervention program, with control offspring. Designed as a quasi-experiment, in which the control group underwent an assessment-only condition, families of both groups completed assessments pre- and post-intervention, as well as at 3- and 6-month follow-ups. Mixed-modelling analyses revealed that improvements in parenting stress mediated the relationship between participation in the RUSH program and reduced offspring internalizing and externalizing symptoms at a six-month follow-up. Taken together, the results show that the OAD may be especially sensitive to stress in the rearing environment as compared to offspring of parents with no affective disorders. Adversity and dysfunction in the home environment might be a particularly salient risk factor for OAD, leading to the development of emotional and behavioural problems, as well as costly mental health interventions. Interventions aimed at improving the rearing environment during childhood may therefore improve developmental outcomes in the OAD and decrease the cost-of-care for these high risk families, as evidenced by the findings of this thesis.