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A prospective cohort study of neurodevelopmental processes in the genesis and epigenesis of schizophrenia
T D Cannon1, I M Rosso, C E Bearden
1Department of Psychology, University of California, Los Angeles 90095-1563, USA.
Insights
Adverse obstetric events, specifically hypoxia, increase schizophrenia risk. Children who later develop schizophrenia show developmental deviations from early childhood, indicating an age-dependent neurodevelopmental trajectory.
Area of Science:
- Neuroscience
- Psychiatry
- Developmental Psychology
Background:
- Schizophrenia's etiology is linked to neurodevelopmental processes.
- Understanding early risk factors and developmental trajectories is crucial.
Purpose of the Study:
- To investigate if adverse obstetric experiences predict schizophrenia.
- To examine developmental trajectories in early childhood for individuals who later develop schizophrenia.
Main Methods:
- Prospective, longitudinal study of 9,236 individuals from the Philadelphia cohort of the National Collaborative Perinatal Project.
- Screening for adult mental health service utilization and chart reviews for DSM-IV diagnoses.
- Analysis of obstetric complications, childhood development, and functional indicators.
Main Results:
- Schizophrenia risk increased linearly with hypoxia-associated obstetric complications.
- Maternal infection and fetal growth retardation were not significant risk factors.
- Preschizophrenic individuals exhibited childhood cognitive, motor, and social deficits, with increasing functional deviance over time.
Conclusions:
- Both genetic and obstetric factors contribute to a neural diathesis for schizophrenia.
- Phenotypic expression of schizophrenia is age-dependent, reflecting brain system maturation.
- Early developmental deviations suggest a long-standing neurodevelopmental basis for schizophrenia.
Abstract:
A number of lines of evidence converge in implicating neurodevelopmental processes in the etiology and epigenesis of schizophrenia. In this study we used a prospective, longitudinal design to examine whether adverse obstetric experiences predict schizophrenia and whether there is a deviant functional-developmental trajectory during the first 7 years of life among individuals who manifest schizophrenia as adults. The 9,236 members of the Philadelphia cohort of the National Collaborative Perinatal Project were screened for mental health service utilization in adulthood, and chart reviews were performed to establish diagnoses according to DSM-IV criteria. The risk for schizophrenia increased linearly with the number of hypoxia-associated obstetric complications but was unrelated to maternal infection during pregnancy or fetal growth retardation. Preschizophrenic cases (and their unaffected siblings who were also cohort members) manifested cognitive impairment, abnormal involuntary movements and coordination deficits, and poor social adjustment during childhood. There was no evidence of intraindividual decline in any domain, but preschizophrenic cases did show deviance on an increasing number of functional indicators with age. Together, these findings suggest that both genetic and obstetric factors participate in creating a neural diathesis to schizophrenia, the phenotypic expressions of which are age dependent, probably reflecting the maturational status of a number of interconnected brain systems.