Children of parents with mental illness are at significantly greater risk for multiple psychosocial problems [1–4]. These children are also more likely to experience developmental delays, lower academic competence and difficulty with social relationships [5–7]. Most inter-generational research has focused on documenting parent–child mental health associations, as parents are typically the most proximal and influential people in a child’s development, particularly during the early years. By virtue of these parent–child mental health relationships, it follows that the mental health histories of grandparents could have some influence on the mental health of their grandchildren. This may occur through a direct relationship with the child, or through their indirect relationship with the child via the parents. Many mental disorders are considered to have a hereditary component to them [8–10], but families also share environments and experiences in addition to their genes.
Studies examining multi-generational mental health relationships have received greater attention in recent years [11–17]. Of the scant literature examining these relationships, there is wide variation in methodologies and in diagnostic tools used to assess mental health problems, including the completeness of family pedigree, the use of direct and indirect assessments and differing interview or questionnaire methods. For example, some of the studies collected mental health data for either maternal or paternal family members [12, 14] where others collected data for both [11, 13]. These variations contribute to a generally mixed and inconsistent range of findings, which we briefly review below.
In the most recent study, Cents et al. [11] found grandparent lifetime anxiety and depression predicted both internalizing and externalizing problems in their 3 year old grandchildren. These associations were independent of parent psychopathology, but were found only when using mother’s, but not father’s, report of children’s internalizing and externalizing problems. Cents et al. also found that for each additional grandparent with a lifetime history of psychiatric disorder, the risk of both internalizing and externalizing problems for children increased by a factor of 1.6–1.7, independent of parental psychiatric disorder.
Using a variety of mental health measures included in the 1970 British Cohort Study, Johnston et al. [17] found a grandparent-parent and parent–child intergenerational mental health correlation of about 0.2. The correlation between grandparent and grandchild mental health was weaker, and the effect persisted across different frequencies of grandparent-grandchild contact. There was no significant grandparent-grandchild correlation once parent mental health was taken into account.
Pettit et al. [14] examined the relationships between grandparent major depressive disorder (MDD), parent psychiatric history, and internalizing problems in children aged 2 to 18 years. They found no evidence of a direct relationship between grandparent MDD and grandchild internalizing problems, however children had higher levels of internalizing problems when both a parent and a grandparent had experienced depression.
Olino et al. [13] examined the extent to which MDD in parents and grandparents, assessed using an array of clinical diagnostic instruments, was related to children’s internalizing and externalizing problems. Parent MDD, grandparent MDD and the interaction of both were associated with children’s internalizing problems at age two. In contrast to Pettit et al. [14], Olino et al. found the presence of MDD in both the parent and grandparent generation did not convey additional risk over and above the direct effect of parent and grandparent MDD on children’s internalizing problems. The presence of grandparent MDD was only associated with internalizing problems in the absence of MDD in both parents.
Weissman et al. [16] used a clinical sample of grandparents to examine the impact of grandparent and parent MDD upon assessments of children’s psychopathology. They found both parent and grandparent MDD was related to children’s psychopathology in middle childhood. They also found children were at greater risk of a mood disorder if they had both a parent and grandparent with MDD. This finding mirrored the results of an earlier study by Warner et al. [15].
Finally, Hammen, Shih and Brennan [12] collected data from a community sample of adolescents, mothers and maternal grandmothers, to examine mental health transmission over three generations, finding that both maternal grandmother and maternal depression had an influence on adolescent mental health. They were unable to assess the influence of paternal depression on children’s mental health outcomes.
These multi-generation studies used different sampling methods and diverse measures of mental health, often collected at a variety of developmental epochs. Several used small samples [15, 16], had limited measures of family socio-demographic environments [12, 13], or lacked mental health data for the full family pedigree [14, 17]. Only one study had complete information on socio-demographic environment and the full family pedigree [11]. Despite these differences, the studies collectively indicate that the mental health histories of grandparents appear to have an effect on children’s mental health, and particularly so in families where mental health problems exist for multiple family members in multiple generations. However, because the pattern of results differs across the studies, it is difficult to ascertain how this occurs. Direct and indirect influences may operate through shared environments, genes, or an interaction of the two.
Grandparents may directly influence the mental wellbeing of their grandchild, which is partially supported by the studies demonstrating a grandparent-grandchild mental health association even in the absence of mental health problems in parents [11, 13, 15, 16]. An example of a direct pathway might be in the way that a grandparent with anxiety disorder interacts with their grandchild. When spending time together, the child may learn through the grandparent’s disposition and behavior that the world should be viewed a frightening place. The child may then learn to become anxious and frightened in general. In such cases, we would expect that the grandparent-grandchild mental health relationship would be stronger in families where children are in frequent contact with their grandparents. Only one of the previous studies examined this idea [17], with results showing that the strength of the grandmother-grandchild mental health association was the same across families with differing frequencies of contact with grandmothers, however the grandmother-grandchild relationship was no longer significant once parent mental health was included in the model.
Such a result suggests that the influence of mental health problems in grandparents could operate indirectly, where the grandparent’s mental health influences parents’ mental health which, in turn, influences the child’s mental health. For example, a grandparent with an anxiety disorder might influence the way their own child views the world. When that child grows up and becomes a parent, at greater risk of anxiety disorder themselves, the parent in turn influences the emotional wellbeing of the grandchild. Thus, the role of grandparents operates via the parent generation. This pathway would be supported by results where the grandparent-grandchild association is no longer observed once parent mental health is accounted for, though this pattern has only been shown in one of the multi-generational studies [17]. Finally, both direct and indirect mechanisms are likely to be in play. Where this occurs we might expect to see an attenuated, though not entirely diminished, relationship between grandparent and grandchild mental health once the mental health of parents has been accounted for. We might also observe an interaction between parent and grandparent mental health on child wellbeing, where the risk of mental health problems in children would increase in terms of both generational proximity and intergenerational burden, which has also been supported by the studies reviewed earlier [11, 14–16].
This study examined multi-generational mental health associations in Australian families in order to further understand the nature of intergenerational mental health associations. We used data from Growing Up in Australia, the Longitudinal Study of Australian Children (LSAC) to investigate how mental health problems in two generations of family members impacted upon children’s subsequent social and emotional wellbeing. Data were collected for over 4,600 children, and included mental health data for mothers, fathers and maternal and paternal grandparents of these children. The LSAC also collects substantial contextual information, including the amount of face-to-face contact children have with their grandparents, along with the family’s social and demographic characteristics. Such data have been relatively rare in other multi-generational studies.
We hypothesized parents would be at greater risk of mental health problems if their own parents (hereafter to be called grandparents) had a history of mental health problems. Second, children would be more likely to have poorer social and emotional wellbeing if they had a grandparent with a history of mental health problems, however this grandparent-child association would be attenuated relative to the more proximal parent–child estimate of association. Finally, we hypothesized that children would have poorer social and emotional wellbeing if they had multiple family members with mental health problems, relative to children with only a parent or grandparent with a mental health problem.