Cognition in schizophrenia: from basic science to clinical treatment

Interest in cognition in schizophrenia has skyrocketed in the past decade, as evidenced by this special issue. This issue is partially based on presentations made at the 5th Biennial Mount Sinai Conference on Cognition in Schizophrenia, in April 2001 in Whistler, B.C., Canada. The first Mount Sinai Meeting in 1993 had 27 attendees and the one in Whistler (from which this issue originated) had 298. The latest meeting, in Colorado Springs in 2003, had 315 attendees. The number of publications on the topic has increased as well, with some journal editors noting that the majority of papers on schizophrenia submitted to their journals are focused on cognitive functioning. The number of papers on cognition in schizophrenia published and presented at major meetings has increased as much as 5-fold in the past 15 years. Further, the NIH has recently acknowledged (Hyman and Fenton 2003) that treatment of cognitive impairment with pharmacological means is an important intervention target, as evidenced by several recent initiatives that are aimed at the treatment of cognitive impairment in schizophrenia through various means. This increase in interest can be traced to two emerging trends. The first is the increased understanding of the functional importance of cognitive impairments in schizophrenia, where it is now widely accepted, in the scientific if not the clinical community, that cognitive impairments are the primary determinant of functional deficits in schizophrenia (e.g. Green 1996; Harvey et al. 1998; Green et al. 2000). Since functional limitations in the illness are responsible for much of the disability that occurs, this is an important revelation and one that has moved the study of cognition in schizophrenia outside the realm of an academic exercise. The second important trend in the field is the increased interest in the neurobiology and treatment of cognitive impairment in schizophrenia. If cognitive deficits are the determinants of functional limitations, it seems logical that treatment of cognitive deficits would lead, all other things equal, to functional improvements. Treatments can be either behavioral in nature or pharmacologically based. Rational pharmacology will progress the most rapidly with the understanding of biological substrates of cognitive impairments. This Special Issue is multifaceted in its topics. They arise from three different sources, including presentations made at the Mount Sinai conference in 2001, articles spontaneously submitted to the journal that addressed the neural bases of cognitive impairments in schizophrenia, and articles that address basic science topics that are relevant to cognitive impairments similar to those seen in schizophrenia. There are three different sections in this issue. The sections include studies of NMDA receptor manipulations, pharmacological manipulation of prepulse inhibition and latent inhibition, and treatment of cognitive impairments in schizophrenia, with a final article describing the US National Institute of Health’s large-scale project on Measurement and Treatment Research Involving Cognition in Schizophrenia (MATRICS). This project itself arises from the increased recognition of the fact that treating cognition in schizophrenia may be the path to improvement in functional outcome in the illness.