HTR2A gene-child abuse interaction and association with a history of suicide attempt among Caucasian depressed psychiatric inpatients

Background: The serotonin transporter gene polymorphism (5HTTLPR) has been associated with vulner-ability for depression after exposure to stressful life event as well as with difference in treatment response to SSRI. Although the A/A genotype of the serotonin receptor SNP (rs7997012) was associated with better citalopram response than the G/G in the STAR*D sample, the effects of this SNP in the moderation of child abuse history on the characteristics of mental illnesses are not well understood. We examined if there are similar gene-environment interaction with the SNP. Methods: Retrospective chart review of 250 Caucasian depressed psychiatric inpatients, who had genotype for rs7997012. Subjects with each genotype were subcategorized into 2 groups with/without history of child abuse. The history of suicide attempts of each group was compared. Results: A trend for an interaction was found between the HTR2A genotype and child abuse history influencing the prevalence of suicide attempts. Although each genotype did not show significant difference in the risk of suicide attempt when there was no abuse history, the A carriers (A/A+A/G) showed significantly higher rate of suicide attempt compared to the G/G when there is a history of child abuse (48.4% versus 22.7% respectively, p=0.0050). The likelihood ratio test from the logistic model showed a trend for an interaction between the A/A genotype and abuse history (Odds Ratio 2.10, X²=2.49, p = 0.11). Limitations: Retrospective study design and small sample size with borderline significance. Conclusions: Our findings showed a potential interaction between the HTR2A gene and stressful life events.