Maternal prenatal depressive symptoms and risk for early-life psychopathology in offspring: genetic analyses in the Norwegian Mother and Child Birth Cohort Study

Abstract

Background. Maternal prenatal depression is a known risk factor for early-life psychopathology among offspring. However, it is necessary to distinguish between potential risk transmission mechanisms. We aimed to test the relative importance of passive genetic transmission, direct exposure, and indirect exposure in the association between maternal prenatal depressive symptoms and later internalizing and externalizing psychopathology. Methods. We used structural equation modelling of phenotypic data and genetically-informative relationships from the families of participants in the Norwegian Mother and Child Birth Cohort Study (MoBa). The analytic sub-sample of MoBa used in the current study comprises 22,195 mothers and 35,299 children. We used mothers’ self-reported depressive symptoms during pregnancy, as captured by the Symptom Checklist (SCL), and their reports of symptoms of psychopathology in their offspring during the first few years of life (measured at 18, 36, and 60 months using the Child Behavior Checklist [CBCL]). Findings. Maternal prenatal depressive symptoms were found to be associated with both internalizing and externalizing problems in early childhood primarily via intergenerationally-shared genetic factors. For internalizing problems, phenotypic transmission also contributed significantly to the association, but was found to be explained by exposure to concurrent maternal depressive symptoms, rather than by direct exposure. Interpretation. Associations between maternal prenatal depressive symptoms and offspring behavioral outcomes in early childhood are likely to be at least partially explained by shared genes. This genetic confounding should be considered when attempting to quantify risks posed by in utero exposure to maternal depressive symptoms.