Using a large longitudinal cohort, we provide evidence that psychopathology in the offspring of depressed mothers is influenced by additional risk exposures closely associated with maternal mental health. More specifically, the present study underscores that, in addition to the debilitating effects of depression in the mother, multiple risk exposures strongly affect child psychopathology – with exposure to each additional risk factor there was at least a 20% increase in the odds for an externalizing and internalizing disorder in boys and girls (see ). For example, a child with three risks factors increased his or her odds for a disorder by approximately 80% (i.e., 1.20*1.20*1.20). These epidemiological data suggest that addressing both maternal depression and associated risk factors may be the most effective manner by which to prevent adverse outcomes in the offspring, and that studies that consider the effect of maternal depression may benefit from also considering other risk factors associated with the mother’s mental health.
As stated, few published research efforts have examined the degree to which additional risk exposures impact child psychopathology above the influence of depression in the mother. Three studies (9
) reported that multiple contextual risks (e.g., low social support, family conflict) had as large an effect on psychopathology in the child as did depression in the mother. However, this research was generally limited by small sample sizes and low rates of contextual risks, such as poverty, housing inadequacy, single motherhood, teen motherhood, and criminal lifestyles. In addition, they typically did not examine clinical levels of child psychopathology. The present research, supports and extends these earlier findings through examining a similar research question in a prospective epidemiological birth cohort of 7,429 mother-child pairs from varied socio-economic and risk backgrounds; and by assessing the predictive impact of maternal depression (child age 1.5 years) and risk exposure of the child (0-2 years) on the child’s externalizing and internalizing DSM-IV based diagnoses at 7.5 years.
Both the present study and the former studies (10
), however, are correlational and were not designed to examine the reasons underlying the overlap of maternal depression with risk factors. For example, risk factors could cause depression in the mother, but depression and risk could also work in a bidirectional manner, whereby increases in one relate to increases in the other, thereby increasing child exposure to both maternal psychopathology and risks associated with mental health in the mother (25
). There is, however, growing evidence from natural experiments, randomized control trials, and other statistically innovative designs that both maternal depression and contextual risk factors like poverty have causal effects on children’s mental health (13
). In future, studies of these kinds could be used to test whether some risk factors have a greater effect than others on child and maternal mental health. For example, it may be that proximal risk factors (e.g., family violence) have a stronger effect on child psychopathology than distal risk factors (e.g., poverty). In the present study, however, we examined a cumulative risk factor, where all risks were equally weighted.
In addition, the present results also help to validate findings that programs that successfully intervene on maternal depression are also associated with improvements – but generally not complete remission – in adverse child outcomes (13
). For example, certain associated risk factors may be more responsive to intervention than others – targetable risks include trying to increase social support network density and to decrease maternal alcohol use and dysfunction in the family. The risk of poverty, which is robustly associated with adverse child outcomes (29
), on the other hand, has been shown to be less responsive to intervention (e.g., 30), but can be successfully buffered by attentive parents who are actively involved in their child’s life (31
). Hence, interventions aimed at reducing depression in the mother and its adverse effects on the children likely need to be informed by the nature of specific risks, their respective impacts on the child, and how they may directly or indirectly respond to an intervention.
Incomplete intervention effects on the child may also be related to at least two developmental sources: (i) the timing of the exposures, and (ii) reciprocal relationships between the mother and the child. With regard to the timing of exposures, the emergence of risk factors in certain periods of development may influence and change a child’s developmental pathway. In the present study, we assessed risk exposure from birth to 2 years of age, a critical developmental period when, for example, brain maturation (i.e., the hippocampus), mother-child attachment and the foundations of cognitive and socio-emotional competence are in play (32
). Early disturbances in normative development can have lasting effects on child well-being (26
). With regard to reciprocal effects, the relationship between maternal depression and child disturbance appears to be bidirectional, such that the child’s problems can contribute to mother’s symptoms which then, in turn, can further increase the child’s problems (33
). If such reciprocal patterns are established early in the life course, an intervention on the child, as well as the mother, is likely necessary (20
The present results should be interpreted in the context of seven main limitations. First, as stated, this research is correlational in nature, hence no causative relationship have been identified. Second, most measures were based on maternal reports, raising the possibility of shared method variance. Future studies should incorporate multiple informants. Third, we relied on self-reports of depressed mothers, which calls into question the accuracy of the reports. That said, studies have found that depressed mothers can be as accurate as other informants about their children’s behavior (34
) and a recent meta-analyses suggested that the size of the effect of maternal depression on child outcomes, as measured by maternal reports on scale formats versus clinical diagnoses, do not significantly differ (35
). Fourth, although the mothers and children of ALSPAC represent a broad spectrum of SES backgrounds, the sample includes relatively low rates of ethnic minorities. The present results will need replication with more ethnically diverse samples. Fifth, like most large longitudinal cohorts, ALSPAC has faced attrition over time. As expected, younger and more socially disadvantaged mothers were more likely to be lost to follow-up. However, although attrition affected prevalence rates of depression in the mother and the externalizing and internalizing disorders in the children, past studies have suggested that the associations between risks and outcomes remained intact, though conservative estimates of the likely true effects (36
). Sixth, we focused on maternal depression and associated risks in the early postnatal period. Earlier (prenatal effects) and later mother, child- and family-based risks may also contribute to differentiating and maintaining early psychopathology in the child, and are important targets for future study. Seventh, in addition to maternal depression, paternal psychopathology has been shown to negatively affect child development (9
). Future research should examine the additive and interactive effects of psychopathology from the mother and father on child wellbeing.