Among the five IgLON family members, both NEGR1 and OPCML have been linked to major depressive disorder [16,17,18,19,20], schizophrenia [21,22,23,24,25,26], autism [27,28], anorexia nervosa [29,30], and Alzheimer’s disease [31,32]. This evidence concerns the gene OPCML and schizophrenia.