In this study, we first investigated the effect of increased expression of selected 3 miRNAs on COMT expression in SH-SY5Y cells, which are used as a model for schizophrenia and we observed that higher levels of miR-30a-5p and miR-34a-5p inhibited COMT expression both on mRNA and protein levels (Fig. 4a–d). The gene discussed is COMT; the disease is schizophrenia.