Association of genetic and environmental factors with suicide risk in alcohol-dependent patients

Abstract

Background: The study aimed to examine association between selected gene polymorphisms (in HTR2A and TPH2 genes), history of childhood abuse, and suicidal behavior in alcohol-dependent patients. Methods: We analyzed genotypes of 364 patients (268 males and 96 females) consecutively admitted to two outpatient and two residential alcohol treatment programs in Warsaw, Poland. Diagnosis of alcohol dependence was made according to DSM-IV criteria by the consensus of an addiction-specialized multidisciplinary team including a psychiatrist and an addiction therapist. DNA was extracted from the white blood cells using the standard procedure. The genotypes of the HTR2A T102C (rs6313) and TPH2 (rs1386494) single nucleotide polymorphisms were analyzed using a Real-Time polymerase chain reaction method. Results: The study indicates that several genetics variants were associated with suicide behavior: 1) HTR2A C102C genotype occurred more frequently in alcohol-dependent individuals who reported suicide attempts than among those without suicidal behavior; 2) coexisting history of childhood abuse and HTR2A C102C variant were strongly correlated with a history of suicidal behavior; 3) female alcoholics who reported suicide attempts had significantly higher frequency of the C102C HTR2A genotype than non-attempters; 4) rs1386494 TPH2 polymorphism was associated with a history of suicide attempts and current suicidal ideation. Conclusions: Suicidal behavior in alcoholism may be associated with genetic variation in serotonin-related genes and coexisting environmental risk factors. These findings may bring therapeutic and etiological implications for the treatment of alcohol dependence and management of patients with high suicidal risk.