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Review
. 2016 Dec 12;15(1):21.
doi: 10.1186/s12952-016-0064-x.

False data, positive results in neurobiology: moving beyond the epigenetics of blood and saliva samples in mental disorders

A Cariaga-Martinez  1 , R Alelú-Paz  2   3
Affiliations
Review

False data, positive results in neurobiology: moving beyond the epigenetics of blood and saliva samples in mental disorders

A Cariaga-Martinez et al. J Negat Results Biomed. .

Abstract

Many psychiatric diseases are influenced by a set of several genetic and environmental factors that genetics alone cannot explain. Specifically, in schizophrenia and bipolar disorder the absence of consistently replicated genetic effects together with evidence for lasting changes in gene expression after environmental exposures suggest a role of epigenetic mechanisms in its pathophysiological mechanisms. In this field, the presence of positive results could potentially uncover molecular mechanisms of deregulated gene expression in these complex disorders. In this commentary we have reviewed the positive data obtained over the last 5 years from the scientific literature published in PubMed and we have shown that these results are based on peripheral samples (blood, saliva and other fluids) that do not allow us to obtain reliable and/or valid results, under any circumstances. Finally, we highlight the need to employ human brain samples in the epigenetic study of mental disorders.

Keywords: Bipolar disorder; Epigenetics; Human brain; Neurobiology; Peripheral samples; Positive results; Schizophrenia.

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Figures

Fig. 1
Fig. 1
Tree Diagram of advanced search in PubMed database. “Schizophrenia” and “Bipolar disorder” were used as Medical Subject Heading (MeSH) main terms while “DNA methylation” was used as simple term. Branches represents the percentage of published reports when these two keywords were combined. The last branch represent the percentage of published reports in first quartile according to impact factors of the corresponding year of publication (Journal Citation Report—Thompson Reuters). Only data from the last 5 years were included
See this image and copyright information in PMC

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