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Intellectual functioning and the long-term course of schizophrenia-spectrum illness.
J W Carter1, J Parnas, A Urfer-Parnas
1Department of Psychology, University of West Georgia, Carrollton, GA, USA. jcarter@westga.edu
Psychological Medicine
|September 24, 2010
Summary
General cognitive deficits are not predictive of schizophrenia spectrum outcomes. Intellectual functioning did not predict psychosis, personality disorders, or functional impairment in a high-risk group.
Area of Science:
- Neuroscience
- Psychiatry
- Genetics
Background:
- Schizophrenia is often viewed as having central cognitive deficits.
- The temporal relationship between intellectual functioning and schizophrenia spectrum illness is not well understood.
Purpose of the Study:
- To investigate the predictive role of intellectual functioning in schizophrenia spectrum outcomes.
- To examine the impact of schizophrenia spectrum illness on intellectual and educational performance.
Main Methods:
- Longitudinal data from the Copenhagen High-Risk Project (CHRP) were analyzed.
- 311 participants (low, high, and super-high risk for schizophrenia) underwent intellectual assessments (WISC/WAIS) at ages 15 and 24.
- Diagnostic and functional assessments were conducted at ages 24 and 42.
Main Results:
- Intellectual functioning showed no predictive relationship to later psychosis or spectrum personality.
- Minimal to no direct relationship was found between intellectual functioning and later work/living, psychiatric treatment, or severity.
- No intellectual decline was associated with psychosis or spectrum personality.
Conclusions:
- Cognitive functioning may play a lesser role in schizophrenia spectrum pathology than commonly believed, particularly in those with a family history.
- Genetic risk, diagnosis, and functional outcomes show strong predictive relationships.
- Findings challenge the centrality of general cognitive deficits in schizophrenia.
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