Preschool Depression and Hippocampal Volume: The Moderating Role of Family Income

Objective: Depression and low socioeconomic status have both been associated with hippocampal volume alterations. Whether these factors interact to predict neurobehavioral outcomes has not been adequately studied. The authors investigated family income as a moderator of the relationship between depression and hippocampal volume in a longitudinal sample.Method: Longitudinal behavioral data, beginning at preschool age, and behavioral and neuroimaging data from school age to adolescence were used to assess the impact of preschool only and total preschool to adolescent depression symptoms on hippocampal volumes using family income as a moderator (N = 176). Results: Depression severity during the preschool period interacted with family income to predict hippocampal volumes at the intercept (ie, age 13 years; B = -0.078, p = .003). Interaction decomposition revealed that only individuals with relatively high family income exhibited smaller hip-pocampal volume with increasing depression severity (B = -0.146, p = .005). Family income was associated with hippocampus volumes only in individuals with low to moderate preschool depression severity (B = 0.289, p = .007 and B = 0.169, p = .030, respectively).Conclusion: Preschool depression severity interacts with family income to predict hippocampal volume across development, such that the effects of early depression are evident only in those with higher income. These findings suggest that hippocampal volume may not be an effective marker of risk for depression at different levels of socioeconomic status, and emphasizes the importance of the environmental context when assessing risk markers for depression. Future research should explore how socioeconomic stress may eclipse the effects of depression on hippocampal development, setting alternative neurodevelopmental risk trajectories.

Automated summary

This study investigated the moderating effect of family income on the relationship between depression and hippocampal volume. The results showed that the severity of preschool depression interacted with family income to predict hippocampal volume. Furthermore, family income was only associated with hippocampal volumes in individuals with low to moderate preschool depression severity.