Neurocognition and Social Cognition in Schizophrenia Patients

V. Roder, A. Medalia

• Editore: S. Karger
• Anno: 2010
• ISBN:
  9783805593397
• Argomento: Medicine
• Categoria: Physiotherapy, Physical Medicine & Rehabilitation

Research shows that neuro- and social cognition have a decisive influence on functional outcome in people with schizophrenia. In this publication, world-renowned experts summarize the latest research on approaches to assessing and treating cognition in schizophrenia. The book is organized to take the reader through the steps from definitions and assessment of cognition to research on the relevance of cognition in everyday life, to chapters which focus on treatments for cognitive disorders. The reader will learn about the NIMH MATRICS initiative which has provided clinicians and researchers with the tools to define and assess neuro- and social cognitive functioning in people with schizophrenia. Then the treatments for neuro and social cognitive deficits are discussed in several chapters which give an overview of cognitive remediation approaches, accompanied by concrete treatment examples. The reader will also learn about the latest results of pharmacological interventions for cognitive deficits. A final chapter focuses on the importance of addressing motivational deficits when treating cognition, and offers treatment approaches to enhance motivation. This publication is essential reading for clinicians and researchers in the fields of psychiatry, psychology as well as students and other professions working with people who have schizophrenia.

Roder V, Medalia A (eds): Neurocognition and Social Cognition in Schizophrenia Patients. Basic Concepts and
Treatment. Key Issues Ment Health. Basel, Karger, 2010, vol 177, pp 1–22

1

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Definition and Measurement of Neurocognition and Social Cognition

Robert S. Kern^a,b · William P. Horan^a,b

^aDepartment of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, and ^bDepartment of Veterans Affairs VISN 22 Mental Illness Research, Education and Clinical Center, Los Angeles, Calif., USA

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Abstract

Disturbances in neurocognition and social cognition are widely recognized as core features of schizophrenia. In this chapter, we provide a critical review of measurement in these 2 areas. For neurocognition, we compare 3 approaches: (a) hybrid batteries, (b) computer-based batteries and (c) the MATRICS Consensus Cognitive Battery. For social cognition, we compare measures used to assess 5 key domains: (a) emotional processing, (b) social perception, (c) social knowledge, (d) attribution bias and (e) theory of mind. We conclude with a section on the promise of developing new treatments in neurocognition and social cognition that will rely, in part, on the advances in measurement Within these areas.

Copyright © 2010 S. Karger AG, Basel

In this chapter we define neurocognition and social cognition, and review methods of measurement in these 2 areas in schizophrenia. The first section on neurocognition will describe and contrast 3 types of neurocognitive batteries: (a) hybrid batteries, (b) computer-based neurocognitive batteries and (c) the MATRICS Consensus Cognitive Battery (MCCB). The second section on social cognition will describe measures commonly used to assess 5 domains within this construct: (a) emotional processing, (b) social perception, (c) social knowledge, (d) attributional bias and (e) theory of mind. We conclude with a section on the promise of developing new treatments for neurocognitive and social cognitive deficits as a means of improving functioning in persons with schizophrenia.

Neurocognition in Schizophrenia

Definition of Neurocognition

The clinical observation that neurocognitive impairment was a primary feature of schizophrenia can be traced back to the early writings of Emil Kraepelin [1] at the turn of the 20th century and his use of the term ‘dementia praecox’ to describe the disorder. He noted that the onset typically occurred in early adulthood (praecox) and resulted in progressive functional and intellectual decline (dementia) in most cases. In his writings on the clinical presentation of dementia praecox, Kraepelin described a wide range of neurocognitive impairments that included disturbances in attention, learning and problem-solving. These disturbances were noted to have marked effects on social behavior, independent living and work functioning.

A general definition provides that neurocognition can be thought of as encompassing all aspects of learning about, understanding and knowing the world around oneself [2]. It includes all of one’s mental abilities, such as attention, perception, memory, language processing, visuospatial ability, executive functions and others used to interact with and make sense of the environment. In schizophrenia research, 7 separable neurocognitive areas have been identified as being of primary interest: attention/vigilance, speed of processing, working memory, verbal learning, visual learning, reasoning and problem-solving as well as social cognition [3]. Of these, social cognition appears to hold a unique place in understanding functioning and will be discussed separately within this chapter.

Neurocognition as a Core Deficit of Schizophrenia

It is widely held that neurocognitive deficits represent a core feature of schizophrenia [4]. That is, they reflect a primary deficit and are not secondary to other features of the illness (clinical symptoms) or treatment-related factors (medication effects) and are common to most, if not all, persons with schizophrenia [2]. For example, a report based on a large, diverse sample indicated that approximately 90% of the persons with schizophrenia show clinically significant levels of impairment in at least 1 neurocognitive domain and 75% show impairment in at least 2 [5]. These figures are probably underestimates when one considers the likelihood that a number of individuals who go on to develop schizophrenia had higher than average premorbid levels of neurocognitive functioning.

Schizophrenia is typically characterized as a disorder with generalized neurocognitive dysfunction that includes specific domains that are more adversely affected than others [6-8]. In chronic, stable outpatient samples, clinically meaningful differences are found between patients and healthy controls across a wide range of neurocognitive domains with effect sizes typically ranging between 0.75 and 1.5 [6]. In the context of these generalized deficits, converging evidence from independent reports and meta-analyses indicates that the impairments to 1 aspect of memory functioning (i.e. learning), commonly measured using list learning tasks, are more severely affected than other areas of neurocognition [6, 7]. The level of neurocognitive impairment remains relatively stable during the adult years (ages 21-55), and persists into late life, when there may be further decline.

Importantly, neurocognitive deficits appear to be relatively independent of the clinical symptoms of the disorder. Although it is somewhat intuitive to expect neurocognitive functioning to be adversely affected by positive symptoms of psychosis (e.g. hallucinations, delusions), there is little evidence to support such a relationship [8-11]. Neurocognitive deficits show a stronger, more consistent relationship with disorganized and negative symptoms (e.g. avolition, alogia, apathy, anhedonia) [12, 13], but the amount of shared variance remains relatively small (5-10%). The relative independence between neurocognitive functioning and clinical symptoms is further supported by data from studies that reveal the persistence of neurocognitive impairments in both psychotic and remitted states [14]. Also, deficits occur in prodromal samples and meta-analyses of family studies of ‘at-risk children and adolescents’ [15].

The scope and severity of neurocognitive deficits seen in persons with schizophrenia do not appear to be secondary to treatment with antipsychotic medications. In general, second-generation antipsychotic medications are not associated with negative effects on neurocognition and may, in fact, convey modest neurocognitive benefits compared to conventional agents [16-19]. It is not clear, however, whether the observed differences are due to the dose levels of conventional agents used in many studies or a reduction in extrapyramidal symptoms and concomitant administration of anticholinergic agents associated with the treatment of second-generation agents [20].

Evidence indicates that the neurocognitive functioning of individuals with schizophrenia is intimately related to real-world functioning. Three reviews of the literature [21-23] show cross-sectional and prospective ties between selected areas of neurocognitive functioning and areas of functional outcome, including community functioning (e.g. broader aspects of work and social functioning), ability to perform instrumental role skills and psychosocial rehabilitation success. For individual cognitive domains, the findings for memory functioning, and verbal learning in particular, appear especially robust [22]. Though more modest degrees of variance are explained at the individual domain level, the amount can be quite large when the effects of neurocognitive functioning are considered more broadly. For example, when multiple neurocognitive domains are included in a summary score, as much as 30% of the variance in functional outcome can be explained [22].

In sum, neurocognitive deficits are seen in most, if not all, persons with schizophrenia, they are relatively independent of psychiatric symptoms and drug effects, and are related to real-world functioning.

Measurement of Neurocognition

The measurement of neurocognition can be carved up in a number of ways. We opted to cover 3 methods that are widely used and provide contrast: (a) hybrid batteries, (b) computer-based batteries and (c) the MCCB [24]. The MCCB used a consensusbased approach to address the shortcomings of other neurocognitive assessment batteries. The following sections describe and critically evaluate these 3 approaches.

Hybrid Batteries

Hybrid batteries are comprised of a number of different neurocognitive tests with the aim of covering a broad range of neurocognitive domains. The number of domains covered by the battery and the number of tests within each domain are controlled by the investigator and are free to vary across studies. The origi...