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.