Serotonin Transporter Gene Polymorphism is Associated with Antidepressant Response to Escitalopram in Multiethnic Malaysians with Major Depressive Disorder: A Preliminary Study

Tiong CP, Loke AC, Mohamed Z, Zainal NZ


Objective: This study investigates the relationship between antidepressant response to escitalopram and polymorphism of the serotonin transporter gene promoter region (5-HTTLPR) in multi ethnic Malaysian patients with Major Depressive Disorder.

Methods: An eight weeks prospective study of treatment response to escitalopram was conducted on 29 Malaysian patients with Major Depressive Disorder. The severity and improvement of depression were assessed with the Montgomery-Asberg Depression Rating Scale. Patients were also genotyped for long (L) and short (S) polymorphisms in 5-HTTLPR using polymerase chain reaction.

Results: Response to escitalopram treatment was more frequent in patients with 5-HTTLPR SS genotype than in those with LL or LS genotypes (p = 0.04, OR = 10.0, 95% CI = 1.05-95.2). The favourable allelic variant for response was S allele (p < 0.01, OR = 4.73, CI = 2.60-8.59). However, there was no difference in the adverse effects rates between the 5-HTTLPR genotype groups (p = 0.39, OR = 2.44, 95% CI = 0.41-14.75).

Conclusion: Polymorphism of 5-HTTLPR was associated with antidepressant response to escitalopram treatment but not to its adverse effects in the Malaysian depressed patients.

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Serotonin Transporter Gene; Polymorphism; Psychopharmacogenetics; Pharmacogenetics

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