Cognitive Impairments in Schizophrenia and Schizoaffective Disorder
Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland.The Journal of nervous and mental disease (Impact Factor: 1.69). 04/2012; 200(4):316-22. DOI: 10.1097/NMD.0b013e31824cb359
The present study aimed to compare population-based familial samples of patients with schizophrenia (n = 218) and schizoaffective disorder (n = 62) and a healthy control group (n = 123). Patients with schizoaffective disorder outperformed patients with schizophrenia in verbal ability, processing speed, visual working memory, and verbal memory. When compared with controls, patients with schizoaffective disorder also had a generalized cognitive impairment. Adjusting for clinical characteristics removed significant differences between the patient groups. Irrespective of the diagnosis, patients with the most severe negative symptoms and highest dose of antipsychotics had the most severe cognitive impairments, whereas mood symptoms were not related to cognitive performance. In conclusion, people with schizoaffective disorder have severe cognitive impairments, but the impairments are milder than in schizophrenia. Mood symptoms may not explain the difference between the diagnostic groups in cognitive functions, but the difference may be related to differences in the severity of negative symptoms.
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- "The effects of antipsychotic medication on cognitive functioning in schizophrenia are unclear. Higher doses of antipsychotic medication have been associated with poorer cognition in cross-sectional, naturalistic studies (Elie et al., 2010; Torniainen et al., 2012). In a metaanalysis of randomized controlled trials with relatively short followups (range 26–78 weeks) there were significant differences between the effects of different atypical antipsychotics on global cognition, and in general, antipsychotic medication enhanced cognition (Désaméricq et al., 2014). "
ABSTRACT: Background: The association between the course of cognition and long-term antipsychotic medication in schizophrenia remains unclear. We analysed the association between cumulative lifetime antipsychotic medication dose and change of verbal learning and memory during a 9-year follow-up. Method: Forty schizophrenia subjects and 73 controls from the Northern Finland Birth Cohort 1966 were assessed by California Verbal Learning Test (CVLT) at the ages of 34 and 43 years. Data on the lifetime antipsychotic doses in chlorpromazine equivalents were collected. The association between antipsychotic dose-years and baseline performance and change in CVLT was analysed, controlling for baseline performance, gender, age of onset and severity of illness. Results: Higher antipsychotic dose-years by baseline were significantly associated with poorer baseline performance in several dimensions of verbal learning and memory, and with a larger decrease in short-delay free recall during the follow-up (p=0.031). Higher antipsychotic dose-years during the follow-up were associated with a larger decrease of immediate free recall of trials 1-5 during the follow-up (p=0.039). Compared to controls, decline was greater in some CVLT variables among those using high-doses, but not among those using low-doses. Conclusion: This is the first report of an association between cumulative lifetime antipsychotic use and change in cognition in a long-term naturalistic follow-up. The use of high doses of antipsychotics may be associated with a decrease in verbal learning and memory in schizophrenia years after illness onset. The results do not support the view that antipsychotics in general prevent cognitive decline or promote cognitive recovery in schizophrenia.
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ABSTRACT: Epigenetic remodeling and modifications of chromatin structure by DNA methylation and histone modifications represent central mechanisms for the regulation of neuronal gene expression during brain development, higher-order processing, and memory formation. Emerging evidence implicates epigenetic modifications not only in normal brain function, but also in neuropsychiatric disorders. This review focuses on recent findings that disruption of chromatin modifications have a major role in the neurodegeneration associated with ischemic stroke and epilepsy. Although these disorders differ in their underlying causes and pathophysiology, they share a common feature, in that each disorder activates the gene silencing transcription factor REST (repressor element 1 silencing transcription factor), which orchestrates epigenetic remodeling of a subset of 'transcriptionally responsive targets' implicated in neuronal death. Although ischemic insults activate REST in selectively vulnerable neurons in the hippocampal CA1, seizures activate REST in CA3 neurons destined to die. Profiling the array of genes that are epigenetically dysregulated in response to neuronal insults is likely to advance our understanding of the mechanisms underlying the pathophysiology of these disorders and may lead to the identification of novel therapeutic strategies for the amelioration of these serious human conditions.Neuropsychopharmacology Reviews advance online publication, 15 August 2012; doi:10.1038/npp.2012.134.
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ABSTRACT: Major psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BP) with psychosis (BP+) express a complex symptomatology characterized by positive symptoms, negative symptoms, and cognitive impairment. Postmortem studies of human SZ and BP+ brains show considerable alterations in the transcriptome of a variety of cortical structures, including multiple mRNAs that are downregulated in both inhibitory GABAergic and excitatory pyramidal neurons compared with non-psychiatric subjects (NPS). Several reports show increased expression of DNA methyltransferases in telencephalic GABAergic neurons. Accumulating evidence suggests a critical role for altered DNA methylation processes in the pathogenesis of SZ and related psychiatric disorders. The establishment and maintenance of CpG site methylation is essential during central nervous system differentiation and this methylation has been implicated in synaptic plasticity, learning, and memory. Atypical hypermethylation of candidate gene promoters expressed in GABAergic neurons is associated with transcriptional downregulation of the corresponding mRNAs, including glutamic acid decarboxylase 67 (GAD67) and reelin (RELN). Recent reports indicate that the methylation status of promoter proximal CpG dinucleotides is in a dynamic balance between DNA methylation and DNA hydroxymethylation. Hydroxymethylation and subsequent DNA demethylation is more complex and involves additional proteins downstream of 5-hydroxymethylcytosine, including members of the base excision repair (BER) pathway. Recent advances in our understanding of altered CpG methylation, hydroxymethylation, and active DNA demethylation provide a framework for the identification of new targets, which may be exploited for the pharmacological intervention of the psychosis associated with SZ and possibly BP+.Neuropsychopharmacology Reviews advance online publication, 5 September 2012; doi:10.1038/npp.2012.125.
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