Title: Premorbid IQ as a predictor for the course of IQ in first onset patients with schizophrenia: A 10-year follow-up study
Authors: van Winkel, Ruud ×
Myin-Germeys, Inez
Delespaul, Philippe
Peuskens, Joseph
De Hert, Marc
van Os, Jim #
Issue Date: Nov-2006
Publisher: Elsevier Science Pub. Co.
Series Title: Schizophrenia Research vol:88 pages:47-54
Abstract: The aim of the present study was to examine the longitudinal course of IQ and its heterogeneity in patients with schizophrenia, from the perspective of the two main "subtypes" of schizophrenia described in the literature: progressive cognitive deficit versus cognitive stabilisation or recovery. Premorbid IQ scores and WAIS IQ scores of 100 first onset patients were obtained at first hospitalization (T1) and after 10 years (T2). Significant changes in IQ over time were found, representing (i) at T1, a deterioration compared to premorbid intelligence (B=-6.3, 95% CI -9.5 to -3.0, p<0.0001), followed by (ii) a recovery at T2 where IQ matched premorbid intelligence again (B=0.5, 95% CI -3.1 to 4.0, p=0.79). In addition, a significant interaction was found between course of IQ over time and estimated premorbid IQ, demonstrating that subjects with lower premorbid IQ levels remained stable over time whereas in individuals with higher premorbid IQ levels a pattern of deterioration was evident at T1, followed by a recovery up to premorbid level at T2. The data confirm the importance of estimated premorbid IQ as an indicator of the longitudinal course of cognitive functioning in patients with schizophrenia and add evidence to the hypothesis of heterogeneity or "subtypes" of schizophrenia. The data, however, do not confirm the existence of progressive deterioration of cognitive functioning. Rather, catching up of cognitive function later in the course of the illness may take place in those whose deficits become apparent in the early phases of illness, whereas those with the most severe premorbid impairments remain stable.
ISSN: 0920-9964
Publication status: published
KU Leuven publication type: IT
Appears in Collections:University Centre Sint Jozef (-)
Research Group Psychiatry
× corresponding author
# (joint) last author

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