Objective: The present study investigated associations between the timing and persistence of maternal psychological disorder and child behaviour problems in a cohort of Pacific 2-year-old children in New Zealand.

Method: Mothers of a cohort of 1398 Pacific infants born in South Auckland, New Zealand were interviewed when their children were 6 weeks, 12 and 24 months of age. Within the context of a wider interview, data regarding maternal mental health were obtained at these times and maternal reports of child behaviour were gathered when the children were 2 years old.

Results: Prevalence rates for internalizing problems were significantly higher in children of mothers who had self-reported symptoms of psychological disorder (11.9% in no symptoms, 27.8% in early symptoms of postnatal depression, 21.1% in late symptoms of psychological disorder and 42.9% in persistent or recurrent symptoms). The adjusted odds ratio (OR) of a child having internalizing problems was 1.38 (95% confidence interval (CI): 0.79-2.43) in those of mothers reporting early symptoms of postnatal depression, 1.45 (95%CI: 0.85-2.49) in late symptoms of psychological disorder, and 2.93 (95%CI: 1.54-5.57) in persistent or recurrent symptoms relative to the no symptoms group. For externalizing problems, the effects of maternal psychological disorder were not significant.

Conclusions: Maternal persistent or recurrent symptoms of psychological disorder may contribute to the behaviour problems of children as young as 2 years old. However, the timing of disorder, whether it is infant or toddler exposure, does not appear to be as crucial. Improved understanding of the associations between maternal psychological disorder and early child behaviour problems may help maternal and child health professionals design appropriate and effective screening and intervention programs to help Pacific mothers and children.