Interactions Between The Genes In Serotonin Pathway And Childhood Trauma On The Dark Triad

The Dark Triad including Machiavellianism,Narcissism,Psychopathy is the dark side of humanity.Few studies have explored the contributions of gene-environment interactions to the individual differences of the dark personalities.This study investigated interactions between the genes in serotonin pathway and childhood trauma in the Dark Triad,which would reveal the mechanism underpin the gene-environment interaction of the Dark Triad.Study 1.Interaction between the genes in 5-HT pathway and childhood trauma on the Dark Triad of prisoners.We measured the Dark Triad and childhood trauma(abuse,neglect)with the Dark Triad Dirty Dozen and Childhood Adverse Experience Questionnaire,genotyped the genetic variations in genes of 5-HT pathway(TPH2,5-HTT,HTR1 A,HTR1B,HTR2 A and MAOA)with polymerase chain reaction-polyacrylamide electrophoresis in 690 male prisoners.Interactions between such genes and childhood trauma by using regression analysis and region of significance test.The results showed that:(1)Interaction between the HTR1 B rs6296 and childhood abuse affected machiavellianism(β=-0.46,p = 0.02)and narcissism(β=-0.61,p = 0.01),with the "Diathesis-stress" model: In case of high childhood abuse,individuals with the CC genotype reported higher score on machiavellian and narcissism(M± SD = 2.12 ± 1.03;3.59 ± 1.01)than ones with GG genotype(1.71 ± 1.06;2.85 ± 1.19).(2)Interaction between the MAOA VNTR and childhood neglect affected machiavellianism(β=-0.37,p = 0.01),with the "Differential susceptibility" model: Individuals with MAOA-L genotype showed lower score(1.09 ± 1.03)than ones with MAOA-H genotype(1.32 ± 0.83)under the low neglect conditions.By contrast,individuals with MAOA-L genotype(1.68 ±0.94)reported higher score than ones with MAOA-H genotype(1.48 ± 0.86)under the high neglect conditions.Study 2.Interactions between the genes in 5-HT pathway and childhood trauma on the Dark Triad of college students.We recruited 698 college sthdents whose Dark Triad and Childhood trauma were determined by deploying the Short-form Dark Triad(SD3)and the Childhood Trauma experience questionnaire(CTQ-SF).The results showed that:(1)Interaction between the HTR1 A rs6295 and childhood abuse affected machiavellianism(β =-0.12,p = 0.01),with the " Diathesis-stress " model: In case of high childhood abuse,individuals with the G allele carriers reported higher score on Machiavellianism(M ± SD = 2.94 ± 0.62)than ones with CC genotype(2.76 ± 0.55).(2)Interaction between the 5-HTTLPR and childhood neglect significantly affected machiavellianism(β = 0.13,p = 0.01),with the " Vantage sensitivity " model: In the low childhood neglect conditions,individuals with LL genotype reported lower score(2.66 ± 0.67)than S allele carriers(2.83 ± 0.57),G allele carriers showed lower score(2.71 ± 0.60)than individuals with AA genotype(2.88 ± 0.56)under the low neglect conditions.(3)Interaction of the MAOA VNTR and childhood neglect significantly affected narcissism(β = 0.10,p <0.01),with the "Differential susceptibility" model: Individuals with MAOA-L genotype(2.95 ± 0.35)showed higher score than ones with MAOA-H genotype(2.75 ± 0.50).By contrast,individuals with MAOA-L genotype reported lower score(2.70± 0.31)than ones with MAOA-H genotype(2.87 ± 0.21)under the high neglect conditions.Interaction between 5-HT genes and childhood trauma significantly impact on machiavellianism and narcissistism:(1)Among prisoners,individuals with HTR1 B rs6296CC genotype showed higher Machiavellianism and narcissism after experiencing high childhood abuse;individuals with MAOA VNTR-L genotype showed lower Machiavellian after experiencing low childhood neglect and shows higher Machiavellianism after experiencing high childhood neglect.(2)Among college students,HTR1 A rs6295 G allele carriers showed higher Machiavellianism after experiencing high childhood abuse;5-HTT LPR L allele carriers and HTR2 A rs6311 G allele carriers showed higher Machiavellianism after experienced low childhood neglect;individuals with MAOAVNTR-L genotype showed higher narcissism after neglect in low childhood,and lower narcissism after experienced low childhood neglect.