Relationship of SERT Polymorphisms to depressive and anxiety symptoms in irritable bowel syndrome

This study investigates the association of psychological symptoms with the distribution of two serotonin transporter gene (SERT) polymorphisms, located in the promoter region (5-HTTLPR) and in intron 2 (STin2 VNTR), in patients with irritable bowel syndrome (IBS). Participants, 21 men and 117 women, were assessed for mental health history and current psychological distress. A blood sample was used for genotyping. Participants who were homozygous for the short allele of 5-HTTLPR or carried a STin2.9 VNTR allele were significantly more likely to have a history of depression. Participants did not differ by genotype in their history of anxiety or suicidal ideation nor in their current levels of depression, anxiety, or general psychological distress. The results support a biopsychosocial model of IBS in which SERT genotype modifies the risk for depressive episodes. Long term, practitioners may individualize treatment of patients with IBS using genotype as one of the factors.