The Latent Taxonicity of Schizotypy in Biological Siblings of Probands With Schizophrenia

Richard J. Linscott*, Sarah E. Morton, Genetic Risk and Outcome of Psychosis (GROUP) Investigators, Jim van Os

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Web of Science)

Abstract

If schizotypy is a taxonic liability for schizophrenia with a general population prevalence of similar to 10%, it should also be taxonic among biological siblings of probands with schizophrenia. Moreover, assuming this is so, siblings' schizotypy class membership should be predicted by probands' familial load for psychotic disorder and clinical severity, consistent with a multifactorial polygenic threshold model of schizophrenia. We tested these hypotheses in the Genetic Risk and Outcome of Psychosis (GROUP) Study where siblings of probands (n = 792) and unaffected controls (n = 559) provided selfreport ratings on the Community Assessment of Psychic Experiences (CAPE). Maximum covariance analyses of control group ratings led to the identification of CAPE items sensitive to nonredundant positive and negative schizotypy classes in the control group (prevalence = 7.9% and 11.1%, respectively). When the same taxonic solution was applied to siblings' CAPE rating, taxometric analyses yielded evidence for larger positive and negative schizotypy classes among siblings (prevalence = 14.1% and 21.8%, respectively). Whereas probands' familial loads for bipolar disorder or drug use disorders did not predict siblings' membership in the schizotypy classes, probands' familial load for psychotic disorder did. Siblings were more likely to be members of the positive schizotypy class where their probands were more severely affected. The pattern of findings is consistent with Meehl's argument that schizotypy reflects liability for schizophrenia.
Original languageEnglish
Pages (from-to)922-932
Number of pages11
JournalSchizophrenia Bulletin
Volume44
Issue number4
DOIs
Publication statusPublished - 1 Jul 2018

Keywords

  • schizotypal personality
  • schizophrenia
  • taxometrics
  • familial risk
  • TAXOMETRIC ANALYSIS
  • GENERAL-POPULATION
  • PSYCHOTIC EXPERIENCES
  • PERSONALITY
  • INDICATORS
  • RISK
  • INSTRUMENT
  • DIMENSIONS
  • DISORDERS
  • VALIDITY

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