AbstractBackgroundCauses of childhood behavior problems remain poorly understood. Enriched family environments and corresponding brain development may reduce the risk of their onset, but research investigating white matter neurodevelopmental pathways explaining associations between the family environment and behavior remains limited. We hypothesized that more positive prenatal and mid-childhood family functioning – a measure of a family's problem solving and supportive capacity – would be associated with two markers of preadolescent white matter neurodevelopment related to reduced behavior problems: higher global fractional anisotropy (FA) and lower global mean diffusivity (MD).MethodsData are from 2727 families in the Generation R Study, the Netherlands. Mothers reported family functioning (McMaster Family Assessment Device, range 1–4, higher scores indicate healthier functioning) prenatally and in mid-childhood (mean age 6.1 years). In preadolescence (mean age 10.1), the study collected diffusion-weighted scans. We computed standardized global MD and FA values by averaging metrics from 27 white matter tracts, and we fit linear models adjusting for possible confounders to examine global and tract-specific outcomes.ResultsPrenatal and mid-childhood family functioning scores were moderately correlated, r = 0.38. However, only prenatal family functioning – and not mid-childhood functioning – was associated with higher global FA and lower global MD in preadolescence in fully adjusted models: β_{global FA} = 0.11 (95% CI 0.00, 0.21) and β_{global MD} = −0.15 (95% CI −0.28, −0.03) per one-unit increase in functioning score. Sensitivity and tract-specific analyses supported these global findings.ConclusionsThese results suggest high-functioning prenatal or perinatal family environments may confer lasting white matter neurodevelopmental benefits into preadolescence.