Influence of catechol-O-methyltransferase enzyme gene polymorphism on alcohol and tobacco consumption in North Indian treatment seeking population.

Background: The co-occurrence of alcohol and tobacco dependence is frequently witnessed in treatment settings. It is a challenge for clinicians to treat such patients due to their powerful biological association. Aim: The study is aimed to assess the relationship of Catechol-O-methyltransferase (COMT) Val158Met polymorphism with substance intake among individuals who are dependent on both alcohol and tobacco. Materials and Methods: A cross-sectional study involving patients coming to the outpatient department was planned. Brief information on their sociodemographic and substance use profile was recorded. Genotyping of COMT Val158Met was carried out using established polymerase chain reaction-restriction fragment length polymorphism method. The COMT genotyping was classified based on the presence or absence of Met allele using the dominant model. Descriptive statistics, Chi-square test, Mann–Whitney test, and Binary logistic regression analysis were performed to analyze the data. Results: The study included 104 alcohol and nicotine co-dependent subjects. More than eighty percent of the participants were educated above secondary level, married, and employed. The allele frequencies of met and Val were found to be 0.23 and 0.77, respectively. Forty percent of the participants reported tobacco-related health problems. The odds of consuming alcohol and nicotine were four times high among Met allele carriers. While the Fagerstrom test for nicotine dependence and heaviness of smoking index scores were up to four and eight times higher among met allele (odds ratio 4.3 and 8.9, respectively). Conclusion: Patients carrying Met allele are reported to consume higher amounts of alcohol and tobacco and were likely to score high among measures of nicotine dependence. Thus met allele carriers needs additional attention for a successful treatment outcome.