Cognitive and Emotional Sequelae of Exposure to Maternal Depression: Memory Functioning as a Neurocognitive Correlate of Internalizing Symptomatology

Abstract

Children exposed to maternal depression are at greater risk for depressive disorders later in life. Researchers have suggested that these youth experience marked stress from the care provided by parents afflicted with mental illness; in turn, chronic exposure to the toxic environment alters neural substrates involved in emotion and stress regulation, such as the hippocampus and prefrontal cortex. However, current literature on neurobehavioral functioning of these at-risk youth relative to healthy peers is sparse and conflicting. Furthermore, it is unclear whether these neurocognitive indices, such as memory functioning, are predictive of internalizing symptomatology in these youth. Accordingly, this study examines the relationships between chronic exposure to maternal depression, severity of mother’s recent symptomatology, and child’s earlier internalizing symptomatology with later memory and psychological functioning (internalizing and externalizing behaviors). A total of 100 children and their parents were assessed when the child was 18 months old and followed up at 5 and 9 years of age. Of these youth, 50 child participants had mothers who had major depression at 18 months (i.e., depressed caregivers, DC), and 50 were those with nondepressed, healthy caregivers (NC). Mothers with depression were coded into three groups: chronic depression, recurrent depression, and non-recurrent depression. Children’s caregiver completed the Child Behavioral Checklist (CBCL) when the child was 18 months, 5 years and 9 years to determine overall internalizing and externalizing symptomatology observed. Child participants also completed the self-report version of the Child Depression Inventory, California Verbal Learning Inventory, and subtests from the Wide Range Assessment of Memory and Learning battery to assess their depressive symptomatology, verbal memory skills, and visual memory functioning respectively. Multiple hierarchical regressions were used to examine associations between chronic maternal depression, recent maternal depression severity, and child’s earlier internalizing symptomatology with later memory and emotional functioning at 9 years. Linear mixed effects model and analysis of covariance were applied to examine the growth pattern for internalizing symptomatology based on the CBCL. Broadly, results indicate that more chronic exposure to maternal depression, but not mothers’ recent symptomatology, is associated with lower verbal memory performance and greater internalizing and externalizing symptoms in the offspring. Internalizing symptomatology of children at age 5 years was not predictive of later memory functioning at 9 years, but was associated with increased internalizing and externalizing symptoms later at 9 years. Importantly, memory functioning, a neurobehavioral index of hippocampal functioning, was not predictive of concurrent psychological functioning (i.e., both externalizing and internalizing symptoms). Finally, both DC and NC youth showed similar non-linear, developmental patterns in their internalizing symptomatology from 18 months to 5 and 9 years; however, DC youth showed elevated symptoms relative to NC peers at baseline, a disparity that persisted by 9 years of age. These findings broadly support the postulation that chronic exposure to maternal depression may impact later hippocampal functioning, as indicated by lower verbal memory performance in offspring. However, findings also indicate that memory performance is not a strong predictor of concurrent psychological functioning, despite that this factor behaviorally indexes the functional status of the hippocampus, a neural substrate involved in stress regulation. Findings highlight importance of engaging depressed mothers in interventions for self and parent-child relationship earlier to reduce the persistent and negative effects of maternal depression on their offsprings’ development.