Superior intellectual ability in schizophrenia: Neuropsychological characteristics

James H. MacCabe, Gildas Brébion, Abraham Reichenberg, Taposhri Ganguly, Peter J. McKenna, Robin M. Murray, Anthony S. David

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Objective: It has been suggested that neurocognitive impairment is a core deficit in schizophrenia. However, it appears that some patients with schizophrenia have intelligence quotients (IQs) in the superior range. In thisstudy, we sought out schizophrenia patients with an estimated premorbid Intelligence Quotient (IQ) of at least 115 and studied their neuropsychological profile. Method: Thirty-four patients meeting diagnostic criteria forschizophrenia or schizoaffective disorder, as defined by the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV), with mean estimated premorbid IQ of 120, were recruited and divided into twosubgroups, according to whether or not their IQ had declined by at least 10 points from their premorbidestimate. Their performance on an extensive neuropsychological battery was compared with that of 19IQ-matched healthy controls and a group of 16 "typical" schizophrenia patients with estimated premorbid IQ<110, using one way ANOVAs and profile analysis using MANOVAs. Results: Schizophrenia patientswhose estimated premorbid and current IQ both lay in the superior range were statistically indistinguishablefrom IQ-matched healthy controls on all neurocognitive tests. However, their profile of relative performancein subtests was similar to that of typical schizophrenia patients. Patients with superior premorbid IQ andevidence of intellectual deterioration had intermediate scores. Conclusions: Our results confirm the existenceof patients meeting DSM-IV diagnostic criteria for schizophrenia who have markedly superior premorbidintellectual level and appear to be free of gross neuropsychological deficits. We discuss the implications ofthese findings for the primacy of cognitive deficits in schizophrenia.

Original languageEnglish
Pages (from-to)181-190
Number of pages10
JournalNeuropsychology
Volume26
Issue number2
DOIs
StatePublished - 2012
Externally publishedYes

Keywords

  • Intelligence
  • Neuropsychologically normal
  • Neuropsychology
  • Psychosis
  • Schizophrenia

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