Testing the Stress Sensitization Hypothesis with a Prospective Sample of Child Welfare Involved and Non-Child Welfare Involved Individuals

Background and Purpose: Negative outcomes for those who experience child maltreatment are well documented. However, the mechanisms through which child maltreatment leads to mental health outcomes like depression and anxiety are not well understood. One hypothesis is children who encounter abuse and neglect develop a sensitivity to later stress exposure that, in turn, increases the likelihood of mental health problems (McLaughlin, Conron, Koenen, & Gilman, 2010). In this prospective study, we investigate whether individuals with substantiated histories of child abuse and neglect are more sensitive than others to later environmental stressors, and whether these stressors elevate their likelihood of experiencing mental health disorders in middle adulthood. 

Methods: Data are from the Lehigh Longitudinal Study (N=457), which began in the 1970s as an evaluation of child welfare agencies. Data were collected from child participants when they were in preschool (18 months - 6 years), school age, adolescence, and adulthood. When last assessed, participants were on average 36 years. At the start of the study, nearly 60% of families were living in poverty, according to federal standards at the time. Current analyses used the gender-balanced full adult sample of 356 individuals.

Outcomes include measures of adult depression, based on scores of the 21-item Beck Depression Inventory, and adult anxiety using the 7-item GAD-7. Substantiated reports of abuse and neglect (maltreatment) are reflected in measures of child welfare (CW) involvement (yes/no), according to data collected at the start of the study. Stress scores at each time point were constructed using 21-items assessing stressful life events and living situations. Control variables included gender, age, educational attainment, marital status, and a standardized measure of SES.

Analyses utilized multiple regression models to test the overall and unique associations between CW involvement and mental health outcomes in adulthood and interactions between CW involvement and stress at each developmental time point.

Results: Findings supported the stress sensitization hypothesis and its impact on adult depression and anxiety. There was a significant interaction between whether participants were CW involved and levels of adult stress in the prediction of both depression and anxiety scores. For those who were maltreated, the impact of proximal stress in adulthood was magnified, and resulted in significantly higher depression and anxiety scores compared to those who were not CW involved. For anxiety scores, the effect of adolescent stress levels combined with CW involvement persisted into adulthood, significantly increasing anxiety scores independent of adult stress levels.

Conclusions and Implications: Results suggest experiences of child maltreatment interact with later stress exposure in the prediction of adult mental health disorders. In this regard, experiences of childhood adversity appear to lower the threshold at which subsequent adverse experiences in turn impact adult mental health. Results add to our understanding of the mechanisms through which early adversity negatively impacts mental health and point to the need for primary and secondary prevention to lessen stress exposure. Providing family supports that limit stressful environments and life events for already vulnerable children appear important for lessening the impact of early maltreatment.