Neurocognitive performance of a community-based sample of young people at putative ultra high risk for psychosis: support for the processing speed hypothesis.

INTRODUCTION: A wide variety of neurocognitive deficits have been reported for help-seeking individuals who are at clinical or ultra high risk for psychosis based on fulfilling set criteria for prodromal syndromes/at risk mental states. We wished to extend this research by conducting the first population-based assessment of prodromal syndromes and associated neurocognition.
METHODS: A sample of 212 school-based adolescents were assessed for prodromal syndromes using the criteria of prodromal syndromes from the Structured Interview for Prodromal Syndromes. The MATRICS consensus neurocognitive battery was used to assess cognitive functioning in this sample.
RESULTS: A total of 8% of the population sample of adolescents met criteria for a prodromal syndrome. These adolescents performed significantly more poorly than controls on two tests of processing speed-Trail-Making Test Part A, F=4.54, p < .01, and the Brief Assessment of Cognition in Schizophrenia Symbol Coding task, F=8.26, p < .0001-and on a test of nonverbal working memory-the Wechsler Memory Scale Spatial Span task, F=3.29, p < .05.
CONCLUSIONS: Adolescents in the community who fulfil criteria for prodromal syndromes demonstrate deficits on a number of neurocognitive tasks. Deficits are particularly pronounced in symbol coding performance, supporting processing speed as a central deficit associated with psychosis risk.