microRNAs as novel biomarkers of schizophrenia (Review)

Schizophrenia is a severe mental illness and the most common complex neuropsychiatric disorder. To date, the etiology of schizophrenia is unclear; consequently, the diagnosis of schizophrenia is controversial. Biomarkers that reflect the dysregulations observed in schizophrenia may potentially assist the diagnosis of the disorder. However, the majority of these biomarkers are found in the brain tissue, which is not readily accessible, leading to the search for novel biomarkers that are present in the peripheral blood. microRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional regulators of gene expression. Previous investigations have revealed that miRNAs may play a potential role in neurodevelopment and maturation, including neurite outgrowth, dendritogenesis and dendritic spine formation. These developments highlight the significance of miRNAs as potential diagnostic biomarkers for schizophrenia. To date, miRNA biomarkers have been predominantly extracted from the brain tissue; however, future studies should examine the use of peripheral blood miRNAs as biomarkers, as these are more accessible.