Introduction to Special Theme Issue

Abstract

The last 2 decades have witnessed a relative explosion of research on cognition in schizophrenia, using a variety of approaches that range from the use of large neuropsychological batteries to focused cognitive experimental techniques. There are several reasons for this surge of research on cognitive function in schizophrenia. One reason is the growing body of research suggesting that cognitive function in schizophrenia is one of the most critical determinants of quality of life in schizophrenia, potentially more so than the severity of other aspects/symptoms of schizophrenia such as hallucinations, delusions, or even negative symptoms.1 A second reason is the hope that understanding the nature of cognitive dysfunction in schizophrenia will give us insight into the neurobiological mechanisms that contribute to the development of this disorder, spurred by the advances made in understanding the neural mechanisms supporting intact cognitive function. A third reason is the hope that cognitive deficits will serve as endophenotypic markers that will help identify genetic or environmental risk factors for the development of schizophrenia. A fourth reason is the hope that understanding the mechanisms leading to cognitive dysfunction in schizophrenia will spur novel drug development and discoveries that may improve cognitive and life function in this illness. As articulated by Gottesman and Hanson,2 the clinical traits used to diagnose schizophrenia, or the subclinical phenomena often used to identify those at risk for schizophrenia, have little biological reality, making it difficult to link them to genetic mechanisms. If at least some cognitive functions have an identifiable link to neurobiological and genetic mechanisms (as recent cognitive neuroscience and functional genomics research suggests), then cognitive deficits may serve as promising endophenotypic markers in the search for the etiology of schizophrenia.3–5