Serotonin transporter polymorphism and potential response to SSRIs in bulimia nervosa

The serotonin transporter (5-HTT) represents the prime target of SSRI antidepressants, and a long (L) and a short (S) variant of the promoter region of the 5-HTT gene, with different transcriptional efficiencies, have been identified. The S allele of the 5-HTT gene-linked polymorphic region (5-HTTLPR) has been associated with poorer SSRI response in major depression. To test the hypothesis that the 5-HTTLPR is associated to SSRI response also in bulimia nervosa, we performed the screening of the 5-HTTLPR in 47 bulimic outpatients undergoing a 12-week treatment with SSRIs plus nutritional counselling in a naturalistic setting. In all, 80% of the SS subjects were nonresponders vs 37.5% of the SL patients and 0.4% of the LL subjects (p<0.0001). This is the first study reporting that the short form of the 5-HTTLPR is significantly associated with a poorer outcome of SSRI therapy in bulimic women undergoing a naturalistic treatment.