Examining pathways between trajectories of maternal depressive symptoms, harsh parenting, and adolescent executive functions: insights from the 2004 Pelotas Birth Cohort

Background: Continuous exposure to maternal depressive symptoms during childhood has been consistently associated with lower executive functions in offspring. However, the pathways linking this association remain poorly examined, with limited research on long-term effects in adolescence and scarce evidence from low- and middle-income countries. Objective: This study aim to investigate the effects of maternal depressive symptom trajectories on adolescents' executive functions, exploring the potential mediating role of harsh parenting. Methods: We utilized data from the 2004 Pelotas Birth Cohort, including 1,949 adolescents followed from birth to 15 years of age. Maternal depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale from 3 months to 11 years. Harsh parenting was measured using the Parent-Child Conflict Tactics Scale at 11 years. Executive functions (sustained attention, working and episodic memory) were evaluated at 15 years using the Cambridge Automated Neuropsychological Test Battery. Path analyses were conducted in MPlus software using structural equation modeling. Results: Of the mothers assessed, 75% belonged to the "moderate-low" or "low" depressive symptom trajectories, while 10.8% were in the "decreasing" trajectory, 9.0% in the "increasing" trajectory, and 5.2% in the "chronic-high" trajectory. Mothers with severe and persistent depressive symptoms during their child's childhood displayed more harsh parenting behaviors (B(SE)=2.428(0.323), 95% CI [1.881, 2.952]), which, in turn, were linked to poorer adolescents’ sustained attention (B(SE)=-0.003(0.001), 95% CI [-0.004, -0.002]) and episodic memory (B(SE) = 0.241(0.107), 95% CI [0.030, 0.452]). No direct association was found between maternal depressive symptoms and executive functions. However, considering harsh parenting as a mediator, it was observed that adolescents whose mothers belonged to the high-chronic trajectory of depressive symptoms exhibited poorer sustained attention (indirect effect: B(SE)=-0.007(0.002), 95% CI [-0.010, -0.004]) and poorer episodic memory (indirect effect: B(SE)=0.717(0.304), 95% CI [0.262, 1.266]) compared to those whose mothers belonged to the low trajectory of depressive symptoms. Conclusions: Severe and persistent maternal depressive symptoms are associated with a higher frequency of harsh parenting behaviors, which in turn affect adolescents' executive functions.Keywords: Executive functions; Maternal depression; Harsh parenting; Adolescent; Path analysis; Cohort study.