Selective serotonin reuptake inhibitors (SSRIs) are known to influence the information processing of emotional material in depressed patients and healthy controls. The functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) has been shown to interact with the effectiveness of serotonin reuptake inhibitors. It is not known whether 5-HTTLPR has an influence on emotional processing in healthy controls. We report first data with long-term SSRI administration after genetic characterization of 5-HTTLPR in a randomized, double-blind, placebo-controlled, crossover design. In 30 healthy controls, 15 homozygous for the long and 15 for the short allele of 5-HTTLPR, emotionally valent images were used to elicit positive or negative emotions. We found a diminished perception of sad and fearful information under SSRI which was significant in the long allele group. These findings emphasize the importance of genetic variance in emotion processing research.
