Schizophrenia bulletin
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Schizophrenia bulletin · Mar 2010
Editorial Comment Historical ArticlePsychiatric genocide: reflections and responsibilities.
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Schizophrenia bulletin · Jan 2010
Semantic expectations can induce false perceptions in hallucination-prone individuals.
Recently, it has been proposed that exaggerated top-down processing may generate spontaneous perceptual output, and that this may constitute a cognitive predisposition toward hallucinations. In this experiment, we investigated whether hallucination proneness would be associated with increased auditory-verbal perceptual expectations, and at which processing level this occurs. From 351 undergraduate students screened for hallucination proneness, using the Launay-Slade Hallucination Scale (LSHS), 42 subjects were recruited for participation. ⋯ This effect remained significant after controlling for general performance on the task. In contrast, hallucination proneness was not associated with phonologically primed errors. We conclude that aberrant top-down processing, particularly in the form of strong semantic expectations, may contribute to the experience of auditory-verbal hallucinations.
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Schizophrenia bulletin · Jan 2010
Catechol-O-methyltransferase Val 158 Met polymorphism and antisaccade eye movements in schizophrenia.
The catechol-O-methyltransferase (COMT) enzyme catabolizes dopamine. The val(158)met single nucleotide polymorphism (rs4680) in the COMT gene has received considerable attention as a candidate gene for schizophrenia as well as for frontally mediated cognitive functions. Antisaccade performance is a good measure of frontal lobe integrity. ⋯ There were no significant associations of genotype with measures of amplitude gain or spatial error (P > 0.2). The results suggest that COMT val(158) carrier status is associated with better performance on the antisaccade task. Possible explanations of this finding are discussed.
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Schizophrenia bulletin · Jul 2009
Meta Analysis Comparative StudyCortical dopamine D2/D3 receptors are a common site of action for antipsychotic drugs--an original patient data meta-analysis of the SPECT and PET in vivo receptor imaging literature.
Subject numbers in neuroreceptor imaging studies of antipsychotic treatment in schizophrenia are generally insufficient to directly test the relationship of regional D(2)/D(3) and 5HT(2A) receptor binding to clinical efficacy. We selected positron emission tomography (PET) and single photon emission computed tomography (SPECT) studies of antipsychotic dose vs occupancy at both temporal cortex and striatal D(2)/D(3) receptors. We selected corresponding SPECT and PET studies of 5HT(2A) receptor occupancy. ⋯ There was no correlation between 5HT(2A) occupancy and clinically effective dose. We conclude that cortical dopamine D(2)/D(3) receptor occupancy is involved in antipsychotic efficacy, with striatal D(2)/D(3) occupancy having a likely therapeutic role while also inducing EPSE. We found no evidence for 5HT(2A) blockade involvement in antipsychotic action, although we cannot exclude this possibility.