Review
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Psychiatr. Mar 22, 2016; 6(1): 102-117
Published online Mar 22, 2016. doi: 10.5498/wjp.v6.i1.102
Biomarkers in schizophrenia: A focus on blood based diagnostics and theranostics
Chi-Yu Lai, Elizabeth Scarr, Madhara Udawela, Ian Everall, Wei J Chen, Brian Dean
Chi-Yu Lai, Elizabeth Scarr, Madhara Udawela, Ian Everall, Brian Dean, the Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3010, Australia
Chi-Yu Lai, Wei J Chen, Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei 100, Taiwan
Chi-Yu Lai, Wei J Chen, Center of Genomic Medicine, National Taiwan University, Taipei 100, Taiwan
Elizabeth Scarr, Ian Everall, Brian Dean, Department of Psychiatry, the University of Melbourne, Parkville, VIC 3010, Australia
Author contributions: Lai CY and Scarr E wrote the paper; Lai CY summarized the review table; Scarr E, Udawela M, Everall I, Chen WJ and Dean B made critical revision in the manuscript; Lai CY and Dean B composed the structures the article; Dean B contributed to the idea of the review.
Supported by The National Science Council of Taiwan, Nos. 102-2917-I-002-002 and 103-2811-B-002-107; the Australian Research Council, No. FT100100689; and the National Health and Medical Research Council, No. APP1002240.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Chi-Yu Lai, PhD, Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, 17 Xu-Zhou Road, Taipei 100, Taiwan. jchiyulai@gmail.com
Telephone: +886-2-33668010 Fax: +886-2-33668004
Received: August 11, 2015
Peer-review started: August 17, 2015
First decision: September 28, 2015
Revised: October 20, 2015
Accepted: December 17, 2015
Article in press: December 18, 2015
Published online: March 22, 2016
Processing time: 218 Days and 9.4 Hours
Abstract

Identifying biomarkers that can be used as diagnostics or predictors of treatment response (theranostics) in people with schizophrenia (Sz) will be an important step towards being able to provide personalized treatment. Findings from the studies in brain tissue have not yet been translated into biomarkers that are practical in clinical use because brain biopsies are not acceptable and neuroimaging techniques are expensive and the results are inconclusive. Thus, in recent years, there has been search for blood-based biomarkers for Sz as a valid alternative. Although there are some encouraging preliminary data to support the notion of peripheral biomarkers for Sz, it must be acknowledged that Sz is a complex and heterogeneous disorder which needs to be further dissected into subtype using biological based and clinical markers. The scope of this review is to critically examine published blood-based biomarker of Sz, focusing on possible uses for diagnosis, treatment response, or their relationship with schizophrenia-associated phenotype. We sorted the studies into six categories which include: (1) brain-derived neurotrophic factor; (2) inflammation and immune function; (3) neurochemistry; (4) oxidative stress response and metabolism; (5) epigenetics and microRNA; and (6) transcriptome and proteome studies. This review also summarized the molecules which have been conclusively reported as potential blood-based biomarkers for Sz in different blood cell types. Finally, we further discusses the pitfall of current blood-based studies and suggest that a prediction model-based, Sz specific, blood oriented study design as well as standardize blood collection conditions would be useful for Sz biomarker development.

Keywords: Schizophrenia; Peripheral blood; Biomarker; Diagnostics; Schizophrenia-associated phenotype; Treatment response; Clinical courses

Core tip: In recent years, there has been search for blood-based biomarkers for schizophrenia (Sz) as a valid alternative. However, it must be acknowledged that Sz is a complex and heterogeneous disorder which needs to be further dissected into subtype using biomarkers. The scope of this review is to critically examine published blood-based biomarker of Sz, focusing on possible uses for diagnosis, treatment response, and their relationship with schizophrenia-associated phenotype. We suggest that a prediction model-based, Sz specific, blood oriented study design as well as standard blood collection procedures would be useful for development of Sz biomarkers.