IQ change over time in schizophrenia and healthy individuals: A meta-analysis

Hedman, Anna M.; Haren, Neeltje E.M. van; Baal, Caroline G.M. van; Kahn, René S.; Pol, Hilleke E. Hulshoff

doi:10.1016/j.schres.2013.01.027

Cited by 62 publications

(53 citation statements)

References 48 publications

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“…Several studies have provided evidence indicating that cognitive and intellectual deficits are evident early in neurodevelopment, well before the onset of psychosis (Fuller et al 2002;Reichenberg et al 2010;Kahn & Keefe, 2013). Evidence also suggests that cognitive deficits are stable at follow-up in both chronic and early years of the illness even though performance of schizophrenia patients might improve less than healthy controls at follow-up (Szöke et al 2008;Bora & Murray, 2013;Hedman et al 2013). Neurodevelopmental theories argue that schizophrenia is related to genetic and non-genetic risk factors leading to abnormal development of the brain that can be associated with problems in acquiring cognitive abilities throughout development (Weinberger, 1986;Murray & Lewis, 1987), and that neurodevelopmental abnormality can be considered as the source of most of the cognitive deficits observed in adults with schizophrenia.…”

Section: Introductionmentioning

confidence: 99%

Neurodevelopmental origin of cognitive impairment in schizophrenia

2014

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Cognitive impairment is a common feature of schizophrenia; however, its origin remains controversial. Neurodevelopmental abnormalities clearly play a role in pre-morbid cognitive dysfunction in schizophrenia, yet many authors believe that schizophrenia is characterized by illness-related cognitive decline before and after onset of the psychosis that can be the result of neurodegenerative changes. The main reasons behinds such arguments include, first, the evidence showing that effect sizes of the cognitive deficits in subjects who develop adult schizophrenia gradually increase in the first two decades of life and, second, the fact that there is functional decline in many patients with schizophrenia over the years. In this Editorial, I argue that current evidence suggests that illness-related cognitive impairment is neurodevelopmental in origin and characterized by slower gain (developmental lag) but not cognitive decline continuing throughout the first two decades of life. I introduce a model suggesting that neurodevelopmental abnormality can in fact explain the course of cognitive dysfunction and variations in the trajectory of functional decline throughout the life in individuals with schizophrenia. In this model, the severity of underlying neurodevelopmental abnormality determines the age that cognitive deficits first become apparent and contributes to the cognitive reserve of the individual. Interaction of neurodevelopmental abnormality with clinical symptoms, especially negative symptoms and aging, vascular changes, psychological and iatrogenic factors contributes to the heterogeneity of the functional trajectory observed in this disorder.

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Section: Introductionmentioning

confidence: 99%

Neurodevelopmental origin of cognitive impairment in schizophrenia

2014

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“…It has been consistently reported that prediction of psychosis can be improved by considering neurocognitive performance measures [40,56]. However, deficits in specific cognitive domains among ARMS and schizophrenia patients are at least in part explained by differences in IQ [31].…”

Section: Introductionmentioning

confidence: 99%

Sex Differences in Cognitive Functioning in At-Risk Mental State for Psychosis, First Episode Psychosis and Healthy Control Subjects

et al. 2015

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The results provide evidence that women generally perform better in verbal learning and memory, independent of diagnostic group (ARMS, FEP, HC). The finding of a shorter reaction time for men in the working memory task could indicate that men have a superior working memory performance since they responded faster during the target trials, while maintaining a comparable overall working memory performance level.

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“…A meta-analysis on IQ changes in patients with schizophrenia concluded that IQ improves less after repeated testing in patients with schizophrenia compared with healthy control participants; however, this conclusion was based on only 8 small case-control studies. 19 A multitude of studies have found that in the general population, intelligence is positively correlated with intracranium (IC) and brain volume. [20][21][22][23] Studies relating IQ changes to brain changes are much more sparse.…”

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confidence: 99%

Association of IQ Changes and Progressive Brain Changes in Patients With Schizophrenia

et al. 2015

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IMPORTANCE Although schizophrenia is characterized by impairments in intelligence and the loss of brain volume, the relationship between changes in IQ and brain measures is not clear.OBJECTIVE To investigate the association between IQ and brain measures in patients with schizophrenia across time. DESIGN, SETTING, AND PARTICIPANTSCase-control longitudinal study at the Department of Psychiatry at the University Medical Center Utrecht, Utrecht, the Netherlands, comparing patients with schizophrenia and healthy control participants between September 22, 2004, and April 17, 2008. Magnetic resonance imaging of the brain and IQ scores were obtained at baseline and the 3-year follow-up. Participants included 84 patients with schizophrenia (mean illness duration, 4.35 years) and 116 age-matched healthy control participants. MAIN OUTCOMES AND MEASURESAssociations between changes in IQ and the total brain, cerebral gray matter, cerebral white matter, lateral ventricular, third ventricles, cortical, and subcortical volumes; cortical thickness; and cortical surface area.RESULTS Cerebral gray matter volume (P = .006) and cortical volume (P = .03) and thickness (P = .02) decreased more in patients with schizophrenia across time compared with control participants. Patients showed additional loss in cortical volume and thickness of the right supramarginal, posterior superior temporal, left supramarginal, left postcentral, and occipital regions (P values were between <.001 and .03 after clusterwise correction). Although IQ increased similarly in patients with schizophrenia and control participants, changes in IQ were negatively correlated with changes in lateral ventricular volume (P = .05) and positively correlated with changes in cortical volume (P = .007) and thickness (P = .004) only in patients with schizophrenia. Positive correlations between changes in IQ and cortical volume and thickness were found globally and in widespread regions across frontal, temporal, and parietal cortices (P values were between <.001 and .03 after clusterwise correction). These findings were independent of symptom severity at follow-up, cannabis use, and the use of cumulative antipsychotic medications during the 3 years of follow-up.CONCLUSIONS AND RELEVANCE Progressive brain tissue loss in schizophrenia is related to relative cognitive decline during the early course of illness.

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IQ change over time in schizophrenia and healthy individuals: A meta-analysis

Cited by 62 publications

References 48 publications

Neurodevelopmental origin of cognitive impairment in schizophrenia

Neurodevelopmental origin of cognitive impairment in schizophrenia

Sex Differences in Cognitive Functioning in At-Risk Mental State for Psychosis, First Episode Psychosis and Healthy Control Subjects

Association of IQ Changes and Progressive Brain Changes in Patients With Schizophrenia

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