Neuropsychological Assessment of Monozygotic Twins Discordant for Schizophrenia

Terry E. Goldberg, J. Daniel Ragland, E. Fuller Torrey, James M. Gold, Llewellyn B. Bigelow, Daniel R. Weinberger

Research output: Contribution to journalArticle

Abstract

A comparison of monozygotic twins discordant for schizophrenia controls for genetic variance and reduces variance due to environmental circumstances, thus serving to highlight differences due to phenotypic-related variables. In this study, we assessed 16 such twin pairs on a wide range of neuropsychological tests. The affected twins tended to perform worse than their unaffected counterparts on most of the tests. Deficits were especially severe on tests of vigilance, memory, and concept formation, suggesting that dysfunction is greatest in the frontotemporal cortex. While manifest symptoms were not highly associated with neuropsychological scores, global level of functioning was. To address the issue of genetic liability, we also compared the sample of discordant unaffected twins with a sample of seven pairs of normal monozygotic twins. No significant differences between the groups were found for any neuropsychological test. In fact, the results suggest that neuropsychological dysfunction is a consistent feature of schizophrenia and that it is related primarily to the clinical disease process and not to genetic or nonspecific environmental factors.

Original languageEnglish (US)
Pages (from-to)1066-1072
Number of pages7
JournalArchives of general psychiatry
Volume47
Issue number11
DOIs
StatePublished - Nov 1990
Externally publishedYes

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ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Psychiatry and Mental health

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