Antidepressant effects of light therapy combined with sleep deprivation are influenced by a functional polymorphism within the promoter of the serotonin transporter gene

Background: A functional polymorphism within the promoter of the serotonin transporter has been shown to influence the antidepressant response to serotonergic drug treatments and to total sleep deprivation (TSD). The short-term relapse that follows acute response to TSD has been successfully prevented by combining TSD with light therapy. The mechanism of action of this combined treatment is unknown. Methods: We tested the hypothesis that allelic variation of the serotonin transporter (5-HTT) linked polymorphic region (5-HTTLPR) could influence the response to the combination of light therapy and TSD. Twenty-two bipolar depressed inpatients were administered a night of TSD combined with 30 min light therapy given during the TSD night and in the morning after recovery sleep. 5-HTTLPR was genotyped using polymerase chain reaction techniques. Changes in perceived mood were rated on a visual analog scale. Results: Light therapy sustained the effect of TSD. The effect was more marked in homozygotes for the long variant of 5-HTTLPR than in heterozygotes and homozygotes for the short variant. Conclusions: The influence of 5-HTTLPR on response to the combination of TSD and light therapy is similar to that observed on response to TSD and serotonergic drug treatments. (C) 2003 Society of Biological Psychiatry.