What have birth cohort studies asked about genetic, pre- and perinatal exposures and child and adolescent onset mental health outcomes? A systematic review.

Increased understanding of early neurobehavioural development is needed to prevent, identify, and treat childhood psychopathology most effectively at the earliest possible stage. Prospective birth cohorts can elucidate the association of genes, environment, and their interactions with neurobehavioural development. We conducted a systematic review of the birth cohort literature. On the basis of internet searches and 6,248 peer-reviewed references, 105 longitudinal epidemiological studies were identified. Twenty studies met inclusion criteria (prospectively recruited, population-based cohort studies, including at least one assessment before the end of the perinatal period and at least one assessment of behaviour, temperament/personality, neuropsychiatric or psychiatric status before 19 years of age), and their methodologies were reviewed in full. Whilst the birth cohort studies did examine some aspects of behaviour and neurodevelopment, observations in the early months and years were rare. Furthermore, aspects of sampling method, sample size, data collection, design, and breadth and depth of measurement in some studies made research questions about neurodevelopment difficult to answer. Existing birth cohort studies have yielded limited information on how pre- and perinatal factors and early neurodevelopment relate to child psychopathology. Further epidemiological research is required with a specific focus on early neurodevelopment. Studies are needed which include the measures of early childhood psychopathology and involve long-term follow-up.