Lay Summary

The mental health of parents may affect the development of mental health problems in their children. We found that mothers’ chronic depression increased the risk of depression at age 21 in their sons but for girls we found that mothers’ chronic depression, particularly when it happened when their daughters were aged 6-8, increased the risk of depression in their daughters. Our study suggests that identifying and treating maternal depression early on is important to prevent mental health problems in children

Background

Maternal depression influences offspring mental health. Yet little is understood about how the duration and timing of maternal depression shapes youth risk for depression, which if understood could inform when best to intervene. This study aimed to determine how the timing and duration of maternal depression was related to offspring depression in late adolescence, and variations by sex

Methods

We used data from the Avon Longitudinal Study of Parents and Children (a prenatal cohort in the Avon area of England, 1991-2003), n=3,301. We applied a structured lifecourse modelling approach to maternal depression (assessed at thirteen points from prenatal period to adolescence) and late adolescent depressive symptoms (age 21, Short Moods and Feelings Questionnaire, SMFQ). Lifecourse models were accumulation (sum of timepoints when maternal depression was reported), sensitive periods (each period assessed as one during which maternal depression has a stronger effect) and instability (frequent fluctuations in maternal depression)

Results

Maternal depression was most common in the prenatal period (21.1% males; 22.2% females). For males, accumulation was the most appropriate model; for each additional period of maternal depression, depressive symptoms in late adolescence increased by 0.11 (95% CI: 0.07,0.15, 1-sided p value≤0.001). For females, exposure to maternal depression was associated with increasing depressive symptoms in late adolescence, with the largest effect in mid-childhood (increase of 0.27 units, 95% CI 0.03-0.50, p=0.015 for difference between mid-childhood and other time-periods) and a smaller, equal effect at all other time-periods (increase of 0.07 units per time-period, 95% CI: 0.03-0.12, p=0.002)

Conclusion

This study highlights the importance of ongoing maternal depression for the development of depression in offspring through to late adolescence. Because long-term exposure to maternal depression was particularly important, early interventions are warranted