An increasing emphasis in the schizophrenia literature has been on the prodromal phase of the illness. The study of schizophrenia spectrum illness, including schizotypal personality disorder, has added important insight into the etiology, neuropathology, and treatment of schizophrenia, which can facilitate early identification, intervention, and perhaps prevention of the illness. The heterogeneity of the schizophrenia spectrum makes its definition elusive at best. The primary aim of the Cognitive Assessment and Risk Evaluation Program at the authors' institution is to combine the current knowledge of clinical and demographic risk factors for schizophrenia with the rapidly emerging data on vulnerability markers, or endophenotypes, that are associated with schizophrenia. The use of brain-based vulnerability markers may help to identify neurobiologically and clinically meaningful subgroups within this heterogeneous population of individuals in the early stages of schizophrenia. Another important aim of the Cognitive Assessment and Risk Evaluation program is to thoroughly assess those individuals who have not converted to psychosis to understand potential protective factors, reduce the rate of false positives, and decrease disability. The current review details a strategy for researching the schizophrenia prodrome by using information gained from research in schizotypal personality disorder.

Introduction Neurodevelopmental processes of adolescence, when superimposed on a vulnerable brain, may produce additive effects reflecting the sub-threshold psychotic symptoms, cognitive and functional deterioration that are the hallmark of the early stages of schizophrenia. Method As part of a longitudinal study, we investigated Continuous Performance Task, Identical Pairs Version (CPT-IP) performance in a sample of 301 participants (At risk for psychosis:109; First Episode: 90 and Controls:102). Performance across groups was compared using d’ of fast and slow, spatial and verbal conditions over two time points. Age effects were investigated using a regression model. Results Across all four CPT-IP conditions FE patients performed significantly worse than controls while AR individuals significantly differed from healthy subjects in the Verbal Condition. Age-related performance associations across groups significantly differed in the slow Verbal Condition because the FE sample did not show a significant association with increasing age like the AR and NC samples. CPT performance was stable over time. Discussion Sustained attention in the putative prodrome of psychosis is not only impaired but associated with age. Research focusing on cognitive and neurobiological age-related changes can help to address fundamental questions about the nature of the disorder, including whether the underlying pathophysiology of early psychosis is static or deteriorating.

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