Sex-specific pathways among tri-allelic serotonin transporter polymorphism, trait neuroticism and generalized anxiety disorder

• Published in: Journal of Psychiatry and Neuroscience 2020, Vol.45 (6), p.379
• Main Authors: Chang, Hsin-An, Fang, Wen-Hui, Liu, Yia-Ping, Tzeng, Nian-Sheng, Shyu, Jia-Fwu, Wan, Fang-Jung, Huang, San-Yuan, Chang, Tieh-Ching, Chang, Chuan-Chia
• Format: Report
• Language: English
• Subjects: Demographic aspects; Generalized anxiety disorder; Genetic aspects; Genetic polymorphisms; Health aspects; Neuroticism; Physiological aspects; Psychological aspects; Serotonin; Sex differences (Psychology); Transport proteins
• ISSN: 1180-4882
• DOI: 10.1503/jpn.190092

Background: Neuroticism personality trait is recognized as an important endophenotypic predictor of generalized anxiety disorder (GAD). Furthermore, endophenotype-based pathway approaches have recently been shown to have greater advantages for gene-finding strategies than traditional case-control studies. In the present study, in addition to conventional case-control methods, we used pathway analyses to test whether the tri-allelic serotonin transporter promoter polymorphism (combining 5-HTTLPR and rs25531) is associated with risk of GAD through its effects on trait neuroticism. Methods: We included 2236 Han Chinese adults in this study, including 736 patients with GAD and 1500 healthy participants. We genotyped the 5-HTTLPR and rs25531 polymorphisms using the polymerase chain reaction restriction fragment length polymorphism method. We used the Neuroticism scale of the Maudsley Personality Inventory (MPI) short version (MPI-Neuroticism) to measure participants' tendency toward neuroticism. Results: Using endophenotype-based path analyses, we found significant indirect effects of the tri-allelic genotype on risk of GAD, mediated by MPI-Neuroticism in both men and women. Compared to women carrying the S'S' genotype, women carrying the L' allele had higher levels of MPI-Neuroticism, which in turn were associated with higher risk of GAD. Men, however, showed the opposite pattern. Using traditional case-control comparisons, we observed that the effect of tri-allelic genotype on GAD was significant, but only in women. Limitations: Participants were restricted to Han Chinese, and we used only 1 questionnaire to assess neuroticism. Conclusion: These findings are the first to show that the triallelic 5-HTTLPR polymorphism is associated with elevated risk of GAD, and that this effect is mediated via increased trait neuroticism, a sex-dependent risk pathway.