Cognitive Impairment in Schizophrenia: Characteristics, Assessment, and Treatment

Cognitive deficits have been long regarded as core features of schizophrenia, but the scope and depth of research in this area has continued to expand at a rapid pace. This book presents recent advancements in the study of cognitive impairments in schizophrenia, with a particular emphasis on literature in the last 10 years. Central themes of the book include the relationship between cognitive deficits and functional capacity, social cognition as a core deficit in schizophrenia, heterogeneity in performance among schizophrenia patients, and cognitive deficits as targets for therapeutic interventions.

The book brings together an impressive group of leading researchers who present literature reviews highlighting recent developments in four primary areas: characteristics of cognitive impairment in schizophrenia (section 1), its functional implications and course (section 2), genetic and biological contributions (section 3), and assessment and treatment of cognitive impairments (section 4). In addition to describing recent progress in each of these areas, the authors suggest several key areas that are promising, or even necessary, areas of future research to continue the field moving forward. Research is needed on how neurocognitive symptoms and particular aspects of negative symptoms interact to determine functional outcome, as well as their relation to fundamental perceptual and motivational processes. The authors suggest that optimal approaches should be determined for combining cognitive remediation and vocational training to enhance occupational functioning and understanding regarding mechanisms of occupational functioning. In addition, future work should investigate interactions among normal age-related cognitive changes and existing deficits in older schizophrenia patients and the functional significance of this cognitive functioning pattern at both the group and individual levels. It is suggested that future revisions of the diagnostic criteria should include consideration of cognitive impairments but also consider that relationships among symptom dimensions and cognitive domains have been more fully investigated for schizophrenia-related symptoms than for mood symptoms. Prospective studies of potential mechanisms underlying cognitive and social cognitive impairments and awareness of illness, as well as translational cognitive neuroscience approaches, are needed in order to develop targeted pharmacological and behavioral intervention strategies.

Consistent with the National Institute of Mental Health’s Research Domain Criteria approach, which aims to generate classifications of mental disorders based on specified domains of brain-behavior constructs, one way the field may progress is through investigation of key cognitive processes, including their occurrence, underlying circuits, course, and associated features across diagnostic categories. The focus of this book is on neurocognition in established schizophrenia; thus, it only touches on schizophrenia-related impairments in groups that are symptomatically at-risk but without psychosis. The rapidly evolving literature on clinical high risk reflects neurodevelopmental and dimensional aspects of cognitive impairments in the psychosis spectrum that are relevant to understanding both the development of underlying circuits and potential for early intervention, amelioration, or perhaps even prevention of psychosis. As the number and type of psychosis risk programs continue to grow, a challenge for the field will be the integration and reconciliation of their findings with the schizophrenia literature reviewed here. Within the Research Domain Criteria framework, it will be important to conduct empirical investigations of the construct validity of impairments in cognitive domains as indices of psychosis risk in order to inform our knowledge of the early course of psychosis, its functional significance, and potential to intervene.

Throughout the book, methods of cognitive and functional assessment are highlighted as fundamental to interpretations of findings in this area, with a critical eye toward existing assessment tools and modifications that may be needed to further advance the field. The assessment section does not aim to comprehensively cover currently used neurocognitive batteries. However, it does provide a discussion of influential tools used in schizophrenia treatment studies, including the Measurement and Treatment Research to Improve Cognition in Schizophrenia battery, which seek to redress gaps in earlier assessment approaches.

Overall, this is an excellent and useful reference for researchers and clinicians seeking an up-to-date review of recent advances in several key areas of cognitive research in schizophrenia. Readers will be informed by consideration of a broader range of functional outcomes than have traditionally been considered and their relationships with cognitive function and remediation/enhancement intervention efforts. Researchers and clinicians alike will be informed by a review of the state-of-the art literature in the field and the many exciting future directions in which this field can grow.