Mood changes after delivery: role of the serotonin transporter gene

Background Polymorphic variations in the serotonin transporter gene ( 5-HTT ) moderate the depressogenic effects of tryptophan depletion. After childbirth there is a sharp reduction in brain tryptophan availability, thus polymorphic variations in 5-HTT may play a similar role in the post-partum period. Aims To study the role of 5-HTT polymorphic variations in mood changes after delivery. Method One thousand, eight hundred and four depression-free Spanish women were studied post-partum. We evaluated depressive symptoms at 2–3 days, 8 weeks and 32 weeks post-partum. We used diagnostic interview to confirm major depression for all probable cases. Based on two polymorphisms of 5-HTT (5-HTTLPR and STin2 VNTR), three genotype combinations were created to reflect different levels of 5-HTT expression. Results One hundred and seventy-three women (12.7%) experienced major depression during the 32-week post-partum period. Depressive symptoms were associated with the high-expression 5-HTT genotypes in a dose–response fashion at 8 weeks post-partum, but not at 32 weeks. Conclusions High-expression 5-HTT genotypes may render women more vulnerable to depressive symptoms after childbirth.