Schizophrenia manifestations 'present from infancy'

Subtle infant motor development delays and adult cognitive deficits are age-dependent manifestations of the same underlying neural processes that give rise to schizophrenia, researchers report.

Their conclusion stems from a new analysis of The Northern Finland 1966 Birth Cohort, a longitudinal population-based survey of 12,068 women and their 12,058 live-born children during 1966.

G Murray (University of Cambridge, UK) and colleagues used hospital records to identify cohort members who had experienced psychosis by the age of 31 years. Sixty-one individuals met the criteria for schizophrenia and underwent cognitive assessment; the team also studied their childhood medical records, which included developmental data.

In addition, 104 gender-matched individuals without schizophrenia were selected from the original cohort to serve as controls.

Their analysis showed that the schizophrenia group achieved neuromotor milestones later and performed significantly worse than controls on all measures of cognition, including categorization, visuospatial working memory, and visual and verbal learning.

Moreover the team identified significant independent associations between infant motor development and adult cognition in the domains of executive function, verbal learning, and visuospatial working memory.

"The pattern of associations between development and cognition was similar in schizophrenia and the general population," Murray's team comments in the journal Schizophrenia Research.

They say that some intellectual deficits are present long before psychosis becomes manifest, suggesting that abnormal neurodevelopment is implicated in the pathogenesis of schizophrenia, perhaps contributing to vulnerability to the disease, or perhaps as an early manifestation of the disease process itself.

"Thus, they may be better considered as part of a single longitudinal syndrome," the researchers conclude.

Schizophr Res 2006; 81: 65-74