ABSTRACT
This purpose of this first chapter is to provide an introduction and overview of the relevant historical basis and clinical research identifying cognitive impairment as a core feature in schizophrenia spectrum disorders. This chapter will briefly review epidemiology and etiology, and what is known and presumed about the natural history of neurocognitive impairment in schizophrenia as related to the clinical course of the illness (from the premorbid period to multi-episode or established illness). We will review what is known about deficits in youth at risk for schizophrenia from family risk and follow-back studies, as well as cognition in the prodromal period from clinical high risk studies. We will cover cognitive predictors of illness onset, the profile and magnitude of deficits in first episode schizophrenia, cognitive changes in people recovering from acute exacerbation, and longitudinal studies of neuro-cognitive impairment in established schizophrenia. We will also provide a brief description of the cognitive profiles of people with schizophrenia and related or spectra disorders. This chapter will conclude with an overview of pertinent clinical issues, many of which will be elaborated in much greater detail in subsequent chapters in this volume.
