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The vulnerability of developing addictions is associated with genetic factors and personality traits. The predisposing genetic variants and personality traits may be common to all addictions or specific to a particular class of addiction. To investigate the relationship between genetic variances, personality traits, and their interactions in addiction are important. We recruited 175 opiate-dependent patients, 102 alcohol-dependent patients, and 111 healthy controls. All participants were diagnosed using DSM-IV criteria and assessed with Tridimensional Personality Questionnaire (TPQ). The dopamine D2 receptor (DRD2), 5-HTT-linked promoter region (5-HTTLPR), and aldehyde dehydrogenase 2 (ALDH2) genes were genotyped using PCR. The genotype frequency of the 5-HTTLPR and ALDH2 was significantly different between the patients and controls (P=0.013, P<0.001, respectively), and borderline significant (P=0.05) for DRD2 polymorphism. Both Novelty Seeking (NS) and Harm Avoidance (HA) scores were higher for patients (P<0.001). After stratification by candidate genes, addicts with ALDH2 *1/*1 interacting with the low-functional group of DRD2 and 5-HTTLPR genes have higher HA traits, whereas addicts with ALDH2 *1/*2 or *2/*2 and low-functional group of DRD2 and 5-HTTLPR genes have higher NS traits. We concluded that addicts, both alcohol- and opiate-dependent patients, have common genetic variants in DRD2 and 5-HTTLPR but specific for ALDH2. Higher NS and HA traits were found in both patient groups with the interaction with DRD2, 5-HTTLPR, and ALDH2 genes. The ALDH2 gene variants had different effect in the NS and HA dimension while the DRD2 and 5-HTTLPR genes did not., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Several studies have hypothesized that genes involved in the dopamine system, including dopamine type-2 receptor (DRD2)-related TaqIA polymorphism and monoamine oxidase-A upstream variable number tandem repeat (uVNTR), may be associated with alcoholism. But their results were contradictory because of alcoholism's heterogeneity. Therefore, we examined whether the DRD2TaqIA and MAOA-uVNTR gene polymorphisms are susceptibility factors for alcoholism comorbid with bipolar disorder (ALC+BP) in Han Chinese in Taiwan., Methods: We recruited 101 Han Chinese men with comorbid alcoholism and bipolar disorder, and 328 healthy male controls from the community. Genotyping was done using PCR-RFLP., Results: There were no significant differences in the genotypic frequencies of the DRD2TaqIA or the MAOA-uVNTR polymorphisms between the 2 groups. The MAOA-uVNTR 3-repeat had a significant protective effect on the ALC+BP (odds ratio=0.432, p=0.035) but not on the healthy controls. However, the interaction between the MAOA-uVNTR 3-repeat and DRD2 A1/A2 was a risk factor in the ALC+BP (odds ratio=3.451, p=0.018)., Conclusions: We indicated the impact of the association between MAOA-uVNTR 3-repeat and DRD2 A1/A2 with ALC+BP., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Several studies have hypothesized that genes regulating the components of the serotonin system, including serotonin transporter (5-HTTLPR) and serotonin 1 B receptor (5-HT1B), may be associated with alcoholism, but their results are contradictory because of alcoholism's heterogeneity. Therefore, we examined whether the 5-HTTLPR gene and 5-HT1B gene G861C polymorphism are susceptibility factors for a specific subtype of alcoholism, antisocial alcoholism in Han Chinese in Taiwan., Methods: We recruited 273 Han Chinese male inmates with antisocial personality disorder (ASPD) [antisocial alcoholism (AS-ALC) group (n=120) and antisocial non-alcoholism (AS-N-ALC) group (n=153)] and 191 healthy male controls from the community. Genotyping was done using PCR-RFLP., Results: There were no significant differences in the genotypic frequency of the 5-HT1B G861C polymorphism between the 3 groups. Although AS-ALC group members more frequently carried the 5-HTTLPR S/S, S/LG, and LG/LG genotypes than controls, the difference became non-significant after controlling for the covarying effects of age. However, the 5-HTTLPR S/S, S/LG, and LG/LG genotypes may have interacted with the 5-HT1B G861C C/C polymorphism and increased the risk of becoming antisocial alcoholism., Conclusion: Our study suggests that neither the 5-HTTLPR gene nor the 5-HT1B G861C polymorphism alone is a risk factor for antisocial alcoholism in Taiwan's Han Chinese population, but that the interaction between both genes may increase susceptibility to antisocial alcoholism.

Background: Several studies have suggested that the serotonin receptor 1B gene (5HT1B) may be important in the pathogenesis of alcohol dependence (alcoholism; ALC; AD). We examined whether 5HT1B gene A-161T polymorphisms (rs130058) are a susceptibility factor for total AD and subgroups of AD. We further explored correlation of this 5HT1B gene variant between anxiety-depression alcoholism (ANX/DEP ALC) and antisocial alcoholism (antisocial ALC) subgroups because of the high comorbidity of anxiety-depression, antisocial personality disorder, and AD., Methods: We recruited 522 Han Chinese in Taiwan for this study: 322 AD patients and 200 controls. The patient group was recruited primarily from medical teaching hospitals; patients with antisocial alcoholism were recruited from Taiwanese prisons. Individuals with AD were classified into 3 homogeneous clinical subgroups -- pure alcoholism (pure ALC), ANX/DEP ALC, and antisocial ALC -- using DSM-IV diagnosis. The 5HT1B gene A-161T polymorphism was determined using PCR-RFLP., Results: No significant differences in genotypic and allelic frequencies were found between controls and the total AD group or between controls and the 3 AD subgroups. However, there were significant differences in the 5HT1B gene A-161T polymorphism at both the genotype and allelic levels between the ANX/DEP ALC and antisocial ALC subgroups., Conclusions: This study suggests that the 5HT1B gene A-161T polymorphism alone is not a risk factor for increasing susceptibility to either AD or its subtypes. However, 5HT1B gene A-161T polymorphisms might be one of the common genetic factors between the ANX/DEP ALC and antisocial ALC subgroups.