Transmission and prevention of depression in the offspring of parents with depression

According to the World Health Organisation, depression is one of the most common psychiatric disorders - affecting around 350 million people across all age groups worldwide. Suffering from major depression not only causes great personal burden for the affected person, but also for their family, society and economy. The later the disease is recognized, the worse is the prognosis, going along with higher treatment costs. Consequently, an early identification of risk factors for depression is necessary to prevent these high personal and economic costs. One of the groups at greatest risk of developing depression is the offspring of parents suffering from depression. Their risk of developing depression is estimated to be three to four times higher during childhood and adolescence alone, and do even persist into adulthood. Since the transmission of depression from parent to child may result from numerous risk and protective factors and their interaction, the high risk for developing a depression is not understood well yet. Furthermore, although evidence-based treatment interventions for depression have been developed and implemented into practice, few prevention programs for the children of depressed parents have been developed, with heterogeneous findings. In the first part of the thesis, I provide a theoretical framework for the trans-generational transmission of depression based on the existing literature. In addition, prevention approaches and their efficiency in reducing the risk for depression are discussed. In the second and empirical part two studies referring to the transmission and prevention of depression in the offspring of depressed parents are reported. In study I, a high-risk group (HR, n = 74) children of parents with depression is compared to a low-risk group (LR, n = 38) consisting of the offspring of parents without depression. The goal of the study was to i) replicate findings of the increased risk in youth that is associated with parental depression and ii) identify most prevalent risk factors in order to explore possible mechanisms of the trans-generational transmission of depression. Therefore, the HR and LR were compared in general psychopathology (self-rated depressive and psychopathology symptoms; parent-rated psychopathology) and the mediators (emotion regulation, attributional style) and moderators (life events). In addition, the role of parental depression and its impact and association on the children’s depressive symptoms is investigated. The data supported earlier findings of increased risk for depression for the HR, since the HR showed significantly increased psychopathology and depressive symptoms with a big effect size (d = 1.75). Thereby, the parental depression was associated significantly with children’s depression severity. In addition, the data provided strong evidence for group differences in adaptive emotion regulation strategies, positive and negative attributional style and the number of positive life events. Against expectations, groups did not differ in maladaptive emotion regulation strategies and the number of negative life events. Maladaptive emotion regulation strategies, negative life events and parental depression were the strongest predictors of children’s depressive symptoms, together accounting for 30.8 % of the variance. These results suggest practical implications for prevention interventions for depression like increasing emotional and cognitive coping strategies and positive life events. Longitudinal highly-powered studies are necessary in future research. In study II, preliminary results of an ongoing randomized controlled trial of one of the most promising prevention programs for the offspring of depressed parents (replicated here for the first time outside of the research group) are presented. Data from n = 61 families who reached post-assessment are provided. It was hypothesized that children in the experimental group (EG) would show decreased symptoms of psychopathology and depression compared to the control group (CG) over time. In addition, mediating factors such as emotion regulation strategies and attributional style were expected to improve within the EG over time. Rating of treatment fidelity was very high, indicating good reliability of the intervention. The acceptance of families of the program was excellent; children and parents gave a very positive feedback about the intervention and their personal benefit of participating. Results indicate significant reduction of self-reported psychopathological symptoms between groups over time favouring a positive intervention effect. In addition, parent-rated psychopathology symptoms also showed significant decreases from baseline to post-assessment. Against expectations, both groups showed significant lower depression. There was a significant interaction effect of time and group indicating less maladaptive emotion regulation strategies and a more positive internal attributional style in the intervention group compared to the control group over time. Both groups showed improved adaptive emotion regulation strategies but a more negative attributional style over the study period. In contrast to predictions, there was a significant interaction effect of time and group in the negative internal attributional style scale, indicating a more negative attributional style of children in the EG over time. The benefits of the CG are interpreted as general activation for this high risk group for seeking information help. Together these findings are promising, although the results are preliminary and a bigger sample is necessary for more confident interpretations. There is a lack of evidence and number of prevention programs for this high-risk group, especially in Germany. Since effect sizes of prevention interventions were found to be small and diminish over time, further research is needed to identify relevant mediators and moderators in order to increase efficacy. In sum, this thesis supports previous findings about the increased risk of depression for the offspring of parents suffering from depression and the association of parental and youth depression. In addition, it provides novel information about particular risk factors for children of depressed parents. Moreover, results of the first replication of a promising prevention intervention in Germany suggest that it is possible to modify some of these risk factors (maladaptive emotion regulation strategies and positive internal attributional style) and that doing so has positive effects on reducing self-reported psychopathology in children at risk