Among the targets of miR-30a-5p, three genes, that is, brain-derived neurotrophic factor (BDNF), mothers against decapentaplegic homolog 1 (SMAD1) and neurogenic differentiation factor 1 (NEUROD1), all known to be associated with schizophrenia and mental disorders, were chosen for further analysis by reverse transcription-quantitative PCR. Here, NEUROD1 is linked to mental disorder.