Does Schizophrenia in Offspring Increase the Risk of Developing Alzheimer's Dementia

Subcortical Structures in Demented Schizophrenia Patients: A Comparative Study

There are few studies on dementia and schizophrenia in older patients looking for structural differences. This paper aims to describe relation between cognitive performance and brain volumes in older schizophrenia patients. Twenty schizophrenic outpatients -10 without-dementia (SND), 10 with dementia (SD)- and fifteen healthy individuals -as the control group (CG)-, older than 50, were selected. Neuropsychological tests were used to examine cognitive domains. Brain volumes were calculated with magnetic resonance images. Cognitive performance was significantly better in CG than in schizophrenics. Cognitive performance was worst in SD than SND, except in semantic memory and visual attention. Hippocampal volumes showed significant differences between SD and CG, with predominance on the right side. Left thalamic volume was smaller in SD group than in SND. Structural differences were found in the hippocampus, amygdala, and thalamus; more evident in the amygdala and thalamus, which were mainly related to dementia. In conclusion, cognitive performance and structural changes allowed us to differentiate between schizophrenia patients and CG, with changes being more pronounced in SD than in SND. When comparing SND with SD, the functional alterations largely coincide, although sometimes in the opposite direction. Moreover, volume lost in the hippocampus, amygdala, and thalamus may be related to the possibility to develop dementia in schizophrenic patients.

Familial Co-Aggregation of Dementia with Schizophrenia: A Cross Sectional Pedigree Analysis

BACKGROUND

Cognitive impairment is the core outcome defining feature in schizophrenia. Schizophrenia, in the context of a broader neurodegenerative conceptualization, may have shared etiology with major neurocognitive disorders (MNCD). To elucidate this association there is definite need to explore the familial loading of dementia, in families of patients with schizophrenia.

METHODS

The authors compared relatives including parental generation and siblings of 100 cases (schizophrenia probands) and 100 controls (anxiety disorder) in order to assess the familial co-aggregation of MNCD. All cases and control were screened with Mini International Neuropsychiatric Interview screen for psychiatric morbidity. The pedigree analysis was conducted by family history method and Family Interview for Genetic Studies. Cognitive impairment in pedigree was screened by community screening instrument for dementia.

RESULTS

There was nonreporting of MNCD in the total 2538 relatives (proband siblings +parental generation) of both cases and controls. Diabetes mellitus was the most common somatic morbidity, found significantly more among the parental generation of cases than healthy controls (χ2 (1, 1713) = 6.452, P < 0.05). The odds of having various psychiatric and medical morbidities in the schizophrenia families compared to control are less than 1.

CONCLUSION

There is no familial co-aggregation of MNCD in schizophrenia probands and common etiology between the two is less likely. Either schizophrenia could be counter-intuitively protective for MNCD or a reversible risk factor that can be prevented by effective treatments.

Relationship between Alzheimer's disease-associated SNPs within the CLU gene, local DNA methylation and episodic verbal memory in healthy and schizophrenia subjects

Genetic variation may impact on local DNA methylation patterns. Therefore, information about allele-specific DNA methylation (ASM) within disease-related loci has been proposed to be useful for the interpretation of GWAS results. To explore mechanisms that may underlie associations between Alzheimer's disease (AD) and schizophrenia risk CLU gene and verbal memory, one of the most affected cognitive domains in both conditions, we studied DNA methylation in a region between AD-associated SNPs rs9331888 and rs9331896 in 72 healthy individuals and 73 schizophrenia patients. Using single-molecule real-time bisulfite sequencing we assessed the haplotype-dependent ASM in this region. We then investigated whether its methylation could influence episodic verbal memory measured with the Rey Auditory Verbal Learning Test in these two cohorts. The region showed a complex methylation pattern, which was similar in healthy and schizophrenia individuals and unrelated to haplotypes. The pattern predicted memory scores in controls. The results suggest that epigenetic modifications within the CLU locus may play a role in memory variation, independent of ASM.

Schizophrenia and risk of dementia: a meta-analysis study

BACKGROUND

Evidence suggests that schizophrenia may be associated with an increased risk of dementia, but results from prior studies have been inconsistent. This study aimed to estimate the relationship between schizophrenia and incident dementia using a quantitative meta-analysis.

METHODS

Several databases were used to gather relevant information, including PubMed, Embase, and Web of Science, with the publication date of articles limited up to December 23, 2017. All studies reported a multivariate-adjusted estimate, represented as relative risk (RR) with 95% confidence intervals (CIs), for the association between schizophrenia and risk of dementia incidence. Pooled RRs were calculated using a random-effects model.

RESULTS

Six studies met our inclusion criteria for this meta-analysis, which included 206,694 cases of dementia and 5,063,316 participants. All individuals were without dementia at baseline. Overall, the quantitative meta-analysis suggested that subjects with schizophrenia were associated with a significantly greater risk of dementia incidence (RR 2.29; 95% CI 1.35-3.88) than those without.

CONCLUSION

The results of this meta-analysis indicate that individuals with schizophrenia may have an increased risk for the development of dementia. Future studies should explore whether schizophrenia is a modifiable risk factor for dementia.