To test the associations between the timing and chronicity of maternal depression symptoms (MDS) and children's long-term verbal abilities.Study design
Participants were 1073 mother-child pairs from a population-based birth cohort in Canada. MDS were assessed at ages 5 months, 1.5, 3.5, and 5 years using the Center for Epidemiologic Studies Depression Scale. Verbal abilities were measured at 5, 6, and 10 years using the Peabody Picture Vocabulary Test-Revised (PPVT-R). Multiple linear regression models were used to estimate the association between timing (early: 5 months and/or 1.5 years vs late 3.5 and/or 5 years) and chronicity (5 months, 1.5, 3.5, and 5 years) of exposure to elevated MDS and children's mean PPVT-R scores.Results
Children exposed to chronic MDS had lower PPVT-R scores than children never exposed (mean difference = 9.04 [95% CI = 2.28-15.80]), exposed early (10.08 [3.33-16.86]) and exposed late (8.69 [1.85-15.53]). There were no significant differences between scores of children in the early compared with the late exposure group. We adjusted for mother-child interactions, family functioning, socioeconomic status, PPVT-R administration language, child's birth order, and maternal IQ, psychopathology, education, native language, age at birth of child, and parenting practices. Maternal IQ, (η2 = 0.028), native language (η2 = 0.009), and MDS (η2 = 0.007) were the main predictors of children's verbal abilities.Conclusions
Exposure to chronic MDS in early childhood is associated with lower levels of verbal abilities in middle childhood. Further research is needed in larger community samples to test the association between MDS and children's long-term language skills.