In this study, we examined the lifetime risk of major depressive episode associated with family disruption and low socioeconomic status in early childhood. Parental divorce by age 7 predicted a greater risk of adult depression. On average, respondents who experienced parental divorce were at twice the risk of depression than those whose parents’ marriages remained intact during their childhood; however, the risk associated with parental divorce was most pronounced when accompanied by a high level of parental conflict. The small number of respondents who experienced the death of a parent in childhood precluded a thorough analysis of long-term depression risk due to loss of a parent. Independent of family disruption, risk of depression was also elevated among children from low socioeconomic status backgrounds.
Limitations
The Providence, R.I., National Collaborative Perinatal Project sample was not designed to be representative of the general U.S. population or of Providence, R.I. However, our finding that low socioeconomic status and family disruption in childhood confer elevated risk for adult depression is consistent with the findings of previous investigations
(7,
8) and suggests that our results are not specific to the present sample. Our sample was selected for the presence or absence of early childhood risk factors for adult psychopathology, including pregnancy/delivery complications and potential learning disabilities
(13,
14). Although the distribution of these potential risk factors in the present sample may differ from the general population, the sampling scheme was accounted for by including controls for the study selection factors in all of the analyses.
Because our analyses of family disruption and socioeconomic status were limited to the period of early childhood, we were not able to examine the impact of childhood conditions beyond age 7 on the risk of depression. However, the early childhood period may be of special importance. In a report based on 935 participants in the Christchurch Health and Development Study, Fergusson et al.
(23) found that parental separation predicted the onset of mood disorders only when it occurred by age 5.
Finally, our analyses of parental conflict have the usual drawbacks of retrospective recall, including the possibility of systematic differences in the reporting of parental conflict according to depression status. Our use of a dichotomous indicator of parental conflict also precluded a more detailed analysis of different kinds of parental conflict and the timing of such conflict with respect to changes in family structure. The measure of parental conflict used in this study likely reflects more severe forms of interpersonal conflict (i.e., physical aggression), although this has not been assessed in validation studies.
Comments
The systematic pattern of association between family disruption and socioeconomic status reflects the underlying reciprocal relations between family composition and economic disadvantage
(10): economic hardship predicts marital strain and dissolution
(24), and single-parent families are at greater risk of experiencing financial difficulties
(25). In the present study, both of these factors contributed independently to an individual’s lifetime risk of depression. Thus, although the socioeconomic circumstances of children frequently decline after changes in parental marital status, such declines do not appear to be the sole reason that family disruption is predictive of depression. In view of the finding that family disruption and socioeconomic status in childhood predicted lifetime depression independent of the adult socioeconomic status of respondents, we conclude that the long-term mental health consequences of childhood conditions are not entirely mitigated by social mobility in adulthood.
Our analyses concern the long-term consequences of childhood disadvantage that occurred during the 1960s. It may be that along with the increasing rates of divorce during the past 40 years, intervening changes in policies and social norms have reduced the impact of family disruption among children today. Unfortunately, this does not seem to be the case. Socioeconomic disadvantage and family disruption continue to be adversely related to cognitive development and mental health among children in current samples
(1,
26,
27).
Our data indicate that the association between childhood family disruption and adult depression can be intensified by family conflict. Since we were unable to determine whether such conflict occurred before divorce or was a result of stresses brought on by the divorce itself, multiple interpretations are possible. One is that predivorce conflict is responsible for long-term depression risk. Block et al.
(28) prospectively observed personality differences between children whose parents subsequently divorced and those whose parents’ marriages remained intact; these differences presumably reflect exposure to predivorce familial conflict. Alternatively, the consequences of divorce may be of primary relevance for the development of depression. In a study of adolescents, Aseltine
(27) found that the longitudinal association between parental divorce and depressive symptoms was attributable to postdivorce stresses rather than to circumstances preceding the divorce. Distinguishing between pre- and postdivorce conflict in future studies is essential for the comparative assessment of these two theories; it will also enable researchers to determine whether parental divorce in some cases may protect the mental health of children if it brings about the cessation of family conflict
(29).
Our study did not permit an elaboration of the pathways linking childhood conditions to the onset of adult depressive disorders. According to existing evidence, the pathways involved will likely comprise factors in the proximal childhood period—including conduct and other psychiatric disorders
(23)—as well as stressors in adult life that are farther removed in time from childhood disadvantage
(30). In addition to identifying psychosocial pathways, a question of central interest concerns the biological translation of psychosocial stressors. Impaired neurodevelopment may be one route of translation, in view of evidence that environmental stressors in utero
(31) as well as developmental delays in childhood
(32) predict adult depression. Stress hormone responsiveness appears to be another promising area for further investigation
(33). Chronic adversity has been linked to disturbances in the hypothalamic-pituitary-adrenal (HPA) axis in children with depression
(34); HPA abnormalities in major depression may also become more pronounced in adulthood
(35).
Further research to identify pathways of risk for major depression will facilitate the development of tailored clinical interventions and policies aimed at mitigating the long-term consequences of childhood disadvantage. At present, results of this study suggest that children from environments characterized by low socioeconomic status and parental divorce are at heightened risk for depression and may therefore benefit from interventions already shown to be effective in reducing risk for depression in other populations deemed at risk
(36,
37).