Review articleCognitive function in schizophrenia: Deficits, functional consequences, and future treatment
Section snippets
Cognitive function in schizophrenia: historical perspective
Kraepelin made the first clinical account of schizophrenia in 1896. He named it dementia praecox—early or premature deterioration. When using this term, Kraepelin referred to the fact that the disorder often strikes in adolescence or early adulthood and runs a chronic, lifelong, disabling course. In his writing about the disorder, Kraepelin put great emphasis on the evident cognitive impairment in individuals he studied, which comprised the deficits in attention, motivation, problem solving,
Cognitive function in schizophrenia: contemporary understanding
The understanding of the fundamental deficits in schizophrenia came full circle as it came to be accepted that cognitive dysfunction plays a central role in the illness as Kraepelin and Bleuler had suggested at the dawn of the twentieth century. Cognitive deficits are a core feature of schizophrenia, which (1) may precipitate psychotic and negative symptoms [7]; (2) are relatively stable over time, with progressive deterioration after the age of 65 in some patients [8]; (3) persist on the
Working memory
Working memory function is thought to be sustained by a network of temporary (as opposed to long-term) memory systems. It plays a crucial role in many cognitive tasks, such as reasoning, learning, and understanding. It refers to the ability to hold the stimuli “on line” for a short time (a few seconds), then either to use it directly after a short delay or to process or manipulate it mentally to solve cognitive and behavioral tasks (eg, to dial a telephone number by holding a number in mind
Functional impairment in schizophrenia
A decline in functioning that has persisted for at least 6 months is required for the diagnosis of schizophrenia. Similar to cognitive deficits, functional deficits are present in most patients at the onset of the illness, and the level of impairment is substantial. Most patients with schizophrenia require some sort of public funds for their support, and this pattern of dependence develops early in the illness. Full recovery is reported in about 20% to 30% of patients with schizophrenia, and
Treatment of cognitive deficits with antipsychotics
As noted earlier, despite being effective in treating positive symptoms, conventional antipsychotics have almost no positive impact on cognitive impairment and produce poor functional outcome [63]. Acute treatment with conventional neuroleptics was found to impair attention and motor processing further [64]; however, these negative effects decrease with long-term treatment. In addition, the most common treatment of extrapyramidal side effects is coadministration of drugs with strong
Summary
This article has discussed the relationship between cognitive deficits and functional outcome in schizophrenia. This relationship was noted first by Kraepelin and Bleuler at the beginning of the twentieth century. With the introduction of conventional neuroleptics, the focus shifted toward the treatment of positive symptoms. In the past few decades, cognitive dysfunction has been recognized as a fundamental feature of schizophrenia and has been shown repeatedly to have a negative association
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