Transmission of parental neuroticism to offspring's depression: The mediating role of rumination

Parental depression has been shown to be a genetic risk factor for depression in offspring (Cohen-Woods, Craig, & McGuffin, 2013; Monroe & Reid, 2008; Plomin et al., 2001; Rice, Harold, & Thapar, 2002). Additionally, there is evidence that parental neuroticism contributes to the genetic transmission of depressive symptoms from parents to offspring (Kendler, Neale, Kessler, Heath, & Eaves, 1993). However, the offspring’s individual characteristics may mediate the relationship between parental factors and the offspring’s risk for depression. One of the most potent of these factors may be maladaptive thinking patterns, particularly rumination (Susan Nolen-Hoeksema, Wisco, & Lyubomirsky, 2008). The current study had two goals: first, to examine the effects of parental depressive symptoms and neuroticism on the offspring’s depressive symptoms; and second, to determine if offspring’s level of rumination mediated this relationship. Rumination (Nolen-Hoeksema, 1991) is a cognitive process that involves repetitive thinking about the causes, situational factors, and consequences of a negative emotional experience. In other words, rumination can be thought of as continuously thinking about and attending to emotionally negative stimuli, in a passive manner, without active problem-solving. Rumination has consistently been found to be a robust and potent predictor of both the onset and maintenance of depression (Hankin, 2008; Nolen-Hoeksema, 2000; Susan Nolen-Hoeksema et al., 2008). Recent twin research suggests that while the heritable influences on rumination are small, they account for the much of the relationship between rumination and depression (Moore et al., 2013). The response styles theory (Nolen-Hoeksema, 1991) was proposed to explain the insidious relationship between rumination and negative affect. Although rumination is related to other negative cognitive styles (e.g. attribution theory (Abramson, Seligman, & Teasdale, 1978), negative automatic thoughts, self-focused attention or private self-consciousness and worry (Papageorgiou & Wells, 2008), Nolen-Hoeksema and colleagues (2008) contend that rumination has a unique relationship to depression. In fact, rumination continues to be related to depression even after controlling for neuroticism and other negative cognitive styles (Papageorgiou & Wells, 2008; Spasojevic & Alloy, 2001). There is evidence that depression is a heritable disorder, as genetics have been found to contribute to the transmission of parental depression to offspring in large twin studies (e.g. Kendler et al., 1986) and in a meta-analysis of studies examining genetic and environmental influences on depression (Sullivan, Neale, & Kendler, 2000). However, these studies also concluded that environmental influences (e.g. the effect of parental pathology on the family climate) were also etiologically significant. Thus, both genes and the environment appear to influence offspring’s risk for depression. Parental neuroticism may also confer vulnerability to depressive symptoms in offspring (Kendler et al., 1993). Neuroticism is one of the dimensions of the five-factor personality model, characterized by a chronic level of emotional instability and proneness to psychological distress (APA, 2006). Neuroticism is a stable personality trait characterized by frequent negative emotional states (e.g. sadness, anger, guilt, anxiety and shame)(Eysenck & Eysenck, 1975; Hirschfeld et al., 1983; McCrae & Costa Jr, 1997). Both cross-sectional (Krueger, 1999) and prospective (e.g. Kendler, Gatz, Gardner, & Pedersen, 2006) studies have found neuroticism to be strongly associated with risk for major depression. Neuroticism also appears to be highly heritable (Clark, Watson, & Mineka, 1994; Plomin et al., 2001), indeed heritability estimates are around 50%. There also appears to be a genetic association between neuroticism and depression, as Kendler and colleagues (1993) concluded that approximately 55% of the genetic liability of major depression appeared to be shared with neuroticism. Thus, parental neuroticism may be genetically transmitted to offspring, increasing their risk for depression. Neuroticism may also increase risk for rumination (Hervas & Vazquez, 2011; Nolan, Roberts, & Gotlib, 1998). Whereas previous studies have not directly examined the association between parental neuroticism and offspring rumination, studies have examined association between neuroticism and rumination within the individual. Specifically, adolescents with high negative affect were more likely to ruminate about stressful events, which then predicted increases in depressive symptoms (Mezulis, & Rudolph, M., 2012). Additionally, in a study of adults, cross-lagged analyses revealed that whereas ruminative self-focus predicted negative affect at a subsequent occasion, negative affect also predicted ruminative self-focus at a subsequent occasion (Moberly & Watkins, 2008). Available research strongly suggests a mediational model in which neuroticism leads to rumination, which in turn is related to depression (Muris, Roelofs, Rassin, Franken, & Mayer, 2005). Research supports a mediational model in clinical and non-clinical samples (Lo, Ho, & Hollon, 2008; Roelofs, Huibers, Peeters, & Arntz, 2008; Roelofs, Huibers, Peeters, Arntz, & van Os, 2008; Spasojevic & Alloy, 2001; Verstraeten, Vasey, Raes, & Bijttebier, 2009). For example, in a study of undergraduates, a mediational model was found in which neuroticism was associated with the cognitive factors of worry and rumination, which in turn were related to anxiety and depression (Muris et al., 2005). In adolescents (aged 14–18), the relationship between neuroticism and depression was found to be mediated by rumination (Mezulis, Priess, & Hyde, 2011). In undergraduates rumination partially mediated the relation between neuroticism and depression (Roelofs et al., 2008). In a sample followed longitudinally from birth to adolescence, rumination significantly mediated the association between infancy negative emotionality and age 15 depressive symptoms (Mezulis et al., 2011). Parental depression and neuroticism may also contribute to a negative family environment (i.e. negative affect, irritability, criticism, guilt, etc.) that increases offspring’s risk for developing maladaptive coping styles such as rumination (Natsuaki et al., 2014). For example, Rice and colleagues (2006) provided evidence for a significant gene-environment interaction whereby genetically vulnerable children and adolescents were at increased risk of developing depressive symptoms if they were also exposed to family conflict. In developing a theoretical model for understanding the transmission of parental depression to offspring, Goodman and Gotlib (1999) commented that depressed parents often express negative cognitions and model maladaptive behaviours and poor coping behaviours. Thus, they proposed that one mechanism of transmission is through offspring learning and copying of the parent’s depressogenic cognitive styles and behaviours. In fact, longitudinal research found that the development of rumination in adolescents was associated with parental expression of emotions such as guilt and sadness (Hilt, Armstrong, & Essex, 2011). Thus, depressed parent’s expression of negative affect (i.e. neuroticism) and negative cognitions during times of stress may deprive children of the opportunity to learn effective coping styles.