Serum autoantibodies such as ANAs, anti-mitochondrial autoantibodies [AMA], anti-gastric parietal cell autoantibodies [APCA], anti-smooth muscle autoantibodies [ASMA], as well as antibodies against liver-kidney microsome [LKM]/ thyroid microsomal (peroxidase) [Tp]/ thyroglobulin [Tg]/ and streptolysin O [ASO]) were screened in a study of 40 OCD patients and compared to 14 patients with other mental disorders including mood, adjustment, psychotic, or anxiety disorders. This evidence concerns the gene CACNA1A and mental disorder.