Previous studies have found several genes that may be associated with migraine combined with depression, including the promoter region of the 5-HT transporter (5HTTLPR) SLC6A4 gene (21), the dopamine receptor gene DRD2 and DRD4 (22), and the GABAergic system of the GABRQ and GABRA3genes (23). This evidence concerns the gene SLC6A4 and depressive disorder.