TPH2 polymorphisms may modify clinical picture in treatment-resistant depression

The association of two tryptophan hydroxylase 2 (TPH2) polymorphisms and treatment response in electroconvulsive therapy (ECT) and the risk of depression was studied. The patient sample consisted of 119 subjects with treatment-resistant major depressive disorder who were treated with ECT. Treatment response was assessed by the Montgomery and Åsberg Depression Rating Scale (MADRS) scores. Patients who had <8 scores in post-treatment MADRS were considered remitters; scores >15 indicated non-response. The polymorphisms studied (rs1386494 and rs1843809) were not associated with treatment response to ECT. However, TPH2 rs1386494 A/A genotype carrying patients had significantly higher MADRS scores before ECT than A/G + G/G genotype carriers (p < 0.001). A/A genotype carriers also had a greater decline in MADRS scores than A/G + G/G genotype carriers during the course of ECT treatment (p = 0.03). This polymorphism may be associated with the severity of treatment-resistant depression. ECT may able to counteract a putative genetically driven worse depressive phenotype.