Attention in Schizophrenia.

Attention is clearly a core area of cognitive dysfunction in schizophrenia, but the concept of "attention" is complex and multifaceted. This chapter focuses on three different aspects of attentional function that are of particular interest in schizophrenia. First, we discuss the evidence that schizophrenia involves a reduction in global alertness, leading to an inward focusing of attention and a neglect of external stimuli and tasks. Second, we discuss the control of attention, the set of processes that allow general goals to be translated into shifts of attention toward task-relevant information. When a goal is adequately represented, people with schizophrenia often show no deficit in using the goal to direct attention in the visual modality unless challenged by stimuli that strongly activate the magnocellular processing pathway. Finally, we discuss the implementation of selection, the processes that boost relevant information and suppress distractors once attention has been directed to a given source of information. Although early evidence indicated an impairment in selection, more recent evidence indicating that people with schizophrenia actually focus their attention more narrowly and more intensely that healthy individuals (hyperfocusing). However, this hyperfocused attention may be directed toward goal-irrelevant information, creating the appearance of impaired attentional filtering.