Association of persistent and severe postnatal depression with child outcomes

Importance: Maternal postnatal depression (PND) is common and associated with negative effects on child development. These effects are not inevitable and it is critical to identify those most at risk. Previous work suggests the risks are increased in the context of persistent PND and PND that is severe, but this has not been systematically studied.
Objective: To examine the long-term effects on child outcomes of differing levels of persistence and severity of PND.
Design: We used the ALSPAC study to examine PND identified at 2 months postpartum that was, and was not, persistent, at three thresholds of severity: moderate, marked, and severe. PND was defined as persistent when the questionnaire score was above threshold at both 2 and 8 months postnatally. For each of these categories, we examined (i) the trajectories of later maternal depression scores (6 time points between 21 months and 11 years after birth), and (ii) child behavioural problems at 3.5 years, school-leaving maths scores at 16 years, and depression at 18 years.
Results Compared to women (average maternal age at delivery 28.5years (SD4.7)) with PND that was not persistent (moderate n=300, marked n=158 or severe n=225) and to women who did not score above threshold at all (n=8878) , for all three severity levels, women with persistent PND (moderate n=129, marked n=75 and severe n=83 ) showed elevated depressive symptoms until 11 years postpartum. PND, whether persistent or not, doubled the risk of child behaviour disturbance. Persistence was particularly important to child outcome in severe PND, substantially increasing the risk for behavioural problems at 3.5 years (OR 4.84, 95%CI 2.94,7.98), for lower maths scores at age 16 (OR 2.65, 95%CI 1.26,5.57), and for depression at age 18 (OR 7.44, 95%CI 2.89,19.11).
Conclusion: Depression tended to follow a chronic course, especially where the early mood disturbance was both persistent and severe. PND that was persistent and severe substantially raised the risk for adverse outcome on all child measures. Meeting criteria for depression both early and late in the postnatal year, especially where the mood disturbance is severe, should alert health care professionals to a depression that is likely to be persistent and be associated with an especially elevated risk of multiple adverse child outcomes. Treatment for this group should be prioritised.
Funding: The UK Medical Research Council, the Wellcome Trust (Grant 092731), and University of Bristol provide core support for ALSPAC.