Objective: This aim of this study was to examine the influence of grandparental (G1) and parental (G2) major depressive disorder (MDD) and other forms of psychopathology on behavior problems in very young offspring (G3).
Method: Oregon Adolescent Depression Project (OADP) participants who had children over a 3-year period were invited to participate in a study of infant and child development. We attempted to collect diagnostic history from the original OADP (G2) participants, their coparents, the parents of the original OADP participants (G1), and the parents of the coparents. Child (G3) outcomes at 24 months of age were based on parent reports of behavior problems.
Results: Univariate correlations indicated that G1 and G2 familial loadings for MDD were associated with higher levels of G3 internalizing and externalizing behavior problems. Multiple regression analyses revealed a significant interaction between G1 and G2 MDD on G3 internalizing (but not externalizing) behavior problems. A higher familial loading for MDD in either the parental or grandparental generation was associated with elevated grandchild internalizing problems, but higher loadings for MDD in both generations did not convey additional risk.
Conclusions: Parental MDD and grandparental MDD are both associated with elevated levels of internalizing problems in young grandchildren, but MDD in both the G1 and G2 generations does not confer additional risk. One important implication is that MDD in the grandparental generation is associated with increased risk to grandchildren even in the absence of parental MDD. Future studies should examine the mechanisms through which grandparental psychopathology influences behavior problems in grandchildren.