Childhood disadvantage, neurocognitive development and neuropsychiatric disorders: Evidence of mechanisms.

PURPOSE OF REVIEW: Children living in socioeconomically disadvantaged households have excess risks of neurodevelopmental and neuropsychiatric problems. The purpose of this review is to synthesize evidence for mechanisms that may contribute to these excess risks. RECENT FINDINGS: The majority of the 60 studies included in our review focused on children's neurocognitive development and behavioural problems. About half conducted mediation analyses of factors in the family and neighbourhood environments, including access to resources (e.g. cognitive inputs within the home environment) and exposure to stressors (e.g. negative parenting practices), as well as neurobiological embedding of childhood disadvantage. In addition, many studies conducted moderation analyses of factors that were hypothesized to interact with (i.e. exacerbate or mitigate) the harmful effects of childhood disadvantage. SUMMARY: Many of the factors that contribute to the excess risk of neurodevelopmental and neuropsychiatric problems among children in disadvantaged households are potentially modifiable (e.g. cognitively stimulating materials, parental language input, cultural resources, parental stress and psychopathology, negative parenting, neighbourhood violence). If their causality is ultimately established, they could be targets for the prevention and reduction of disparities. The continued search for mechanisms should not detract from work to reduce and hopefully eliminate children's exposure to disadvantage.