Trajectory of Neurocognitive Functioning in Psychotic Disorders

Student thesis: Doctoral ThesisDoctor of Philosophy


Although cognitive deficits are recognised as a core feature of schizophrenia, their trajectory over the course of the illness is still debated. The primary objectives of this thesis were: (i) to determine the neuropsychological profile at the first episode of psychosis (Chapter 3); (ii) to examine gender differences in the profile of neuropsychological performance (Chapter 4) and (iii) to determine if cognitive abilities decline, remain static or modestly improve throughout the course of psychotic illness (Chapter 5). The first (baseline) analyses form part the AESOP (Aetiology and Ethnicity in Schizophrenia and Other Psychoses) study, a population based, case-control study of first-episode psychosis recruited over a three-year period between September 1997 to August 2000 in London, Bristol and Nottingham. The second analyses (follow-up, where I followed 108 patients and 103 healthy controls) also form part the AESOP study, conducted 6 to 10 years afterwards but only in London and Nottingham. In this thesis I found that early in the course of psychotic illness cognitive deficits are present in all psychotic disorders, but are most severe and pervasive in schizophrenia and least pervasive in bipolar. There was strong evidence for gender differences in neuropsychological performance but these differences were disorder specific. Gender related factors appear to moderate the severity of cognitive deficits in bipolar/mania and depressive psychosis patients. Future schizophrenia patients had an early static developmental impairment on measures relying on knowledge acquisition (verbal IQ). This static deficit increases in size starting in late adolescence or early adult life. There was also an increase in deficit on memory functions. Future bipolar patients had normal or slightly above normal knowledge acquisition scores (verbal IQ) which started to deteriorate starting in early adult life.
Thus, both schizophrenia and bipolar/mania patients show dynamic changes in general and specific cognitive functions which start early in childhood and continue across the life span. Both depressive psychosis and other psychotic disorders show different age related changes than schizophrenia or bipolar/mania. However because of small sample size and lack of studies examining the premorbid period therefore it is difficult to provide a life course model.
Date of Award2012
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorAvi Reichenberg (Supervisor), Kevin Morgan (Supervisor) & Robin Murray (Supervisor)

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