In a previous study, mmu_circ_0001223 (derived from Bnc2 gene, also called circ‐Bnc2) was found to be significantly downregulated in a chronic unpredictable mild stress mice model, and its overexpression could promote the protein expression of CREB1 and BDNF to alleviate depression progression (Zhang et al., 2018). This evidence concerns the gene BNC2 and major depressive disorder.