when the child was 11 years old using the Edinburgh Postnatal Depression Scale (EPDS)—this measure has been validated outside the postnatal period [24]. As scores of >12 are highly associated with a diagnosis of a depressive disorder, this cut off was used to indicate the presence of depression [25]. Analyses also adjusted for child factors including gestational age (≤36 or ≥37 weeks), birth weight and gender. As parental and child educational attainment are strongly associated, analyses for KS2 outcomes were further adjusted for highest level of paternal education (as reported by the mother and categorised similarly).
