Role of serotonergic gene polymorphisms on response to transcranial magnetic stimulation in depression

Transcranial magnetic stimulation (TMS) has been extensively studied as a treatment for Major Depression. However, no data are available about the role of genetic variables on the response to this treatment. We analysed the role of two polymorphisms that influence the response to antidepressants: the polymorphisms of the serotonin transporter promoter region (SERTPR) and of the 5-HT1A serotonergic receptor promoter region (-1019C/G). Ninety-nine patients from two double-blind, randomised, sham-controlled TMS trials were enrolled. There was a significant influence (p = 0.016) of the SERTPR polymorphism on treatment outcome, without differences between active and sham stimulation. Conversely, there was a significant (p = 0.014) interaction between 5-HT1A genotype and type of stimulation: C/C patients showed a higher difference between active and sham stimulation, indicating that these patients benefited more by TMS than C/G and G/G subjects. Our sample has not the power to control for the possible influence of different medications on these results.