ANKIB1 and major depressive disorder: For example, circ-Ankib1 and circAnks1a are involved in the development of neuropathic pain (Zhang S. B. et al., 2019); circRNA_104670 and circSEMA4B are involved in low back pain (Lin et al., 2021); circSlc7a11 overexpression is involved in bone cancer pain (Chen et al., 2021); and circSTAG1 was significantly decreased in the hippocampus of chronic unpredictable stress-treated mice and the peripheral blood of patients with major depressive disorder (Huang et al., 2020).