Personality traits influence risk for suicidal behavior. We examined phenotype- and genotype-level associations between the Big Five personality traits and suicidal ideation and attempt in major depressive, bipolar and schizoaffective disorder, and schizophrenia patients (N = 3012) using fixed- and random-effects inverse variance-weighted meta-analyses. Suicidal ideations were more likely to be reported by patients with higher neuroticism and lower extraversion phenotypic scores, but showed no significant association with polygenic load for these personality traits. Our findings provide new insights into the association between personality and suicidal behavior across mental illnesses and suggest that the genetic component of personality traits is unlikely to have strong causal effects on suicidal behavior.
Drug addiction is a multifactorial disorder. Researchers have posited that an individual's inherited behavioral propensity or temperament contributes to the disorder by shaping a personality strongly linked with the risk of drug abuse. Further, they hypothesize that the polymorphism of dopamine D2 receptor increases the susceptibility to and severity of addiction. We, therefore, investigated possible associations between dopamine D2 receptor (DRD2) and personality traits among intravenous heroin addicts.
Three single nucleotide polymorphisms (SNPs) in alcohol-metabolizing genes - ADH1B (Arg47His), ADH1C (Ile350Val) and ALDH2 (Glu504Lys) have been extensively associated with flush reaction and alcoholism. Therefore, we investigated the association of these three SNPs with alcohol-induced reactions (AIRs), alcoholism risk, personality and anthropometric traits among Malaysian university students. AIRs, Self-Rating of the Effects of Alcohol (SRE) and Ten-Item Personality were surveyed, anthropometric measurements and DNA samples were taken. Among 264 valid drinkers (111 males, 153 females; 229 ethnic Chinese, 35 ethnic Indians), the minor allele frequencies for ADH1B, ADH1C, ALDH2 among Chinese/Indians were .45/.07, .33/.40, .32/.41, respectively; distribution of ADH1B alleles significantly different between ethnicities. Current/former experiences of flushing, hives, heart palpitations after alcohol consumption; and sleepiness, headache reactions, early and overall SRE were significantly different between ethnicities and genders, respectively. Overall SRE score was associated with ADH1C and ALDH2 alleles. 'Openness to Experiences' was associated with ALDH2 genotypes and alleles; Glu/Glu or Glu carriers showed significantly higher means. ADH1B Arg/Arg and Arg carriers showed significantly higher total body and subcutaneous fats but association was abolished after controlling for ethnicity. In conclusion, gender and ethnicity, but not alcohol-metabolizing gene variants, play a role in influencing the manifestation of AIRs.