A. Fouad¹, R. Gomaa^{1, 2,}, M. Farag¹

Drug dependence is considered a major contributor to both medical morbidity and mortality all over the world. It also represents an important health problem that has a great impact on the person's life both socially and economically. It was suggested that there is a substantial genetic contribution to drug dependence vulnerability. Cannabinoid receptors are known to be activated by natural as well as synthetic cannabinoids. Several evidences suggested that improved information about Cannabinoid receptor genes and their human variants might add to the understanding of vulnerabilities to drug dependence. The current study aimed at investigating the possible association between the cannabinoid receptor gene and drug dependence. The study was conducted on 150 drug dependent individuals. The diagnosis of drug dependence was based on the current Diagnostic and Statistical Manual of Mental disorders (DSM-IV) and urine screening tests. These individuals were using either Cannabis or Tramadol solely or in combination. All drug dependent individuals were males and all were current smokers. The duration of drug abuse ranged from 1 to 9 years. All participants were screened for a nucleotide polymorphism in cannabinoid receptor 2 gene (CB2) by PCR amplification and HapII Restriction Fragment Length Polymorphism analysis. The study has proved a significant association between occurrence of polymorphism in the Cannabinoid Receptor 2 gene and drug dependence, where 83.3% of drug dependents showed the polymorphism compared to 15% of the control group. A significant association was also detected between the presence of this polymorphism and family history of drug dependence and.The results of the present study confirmed the possible role of Cannabinoid Receptor 2 gene in drug dependence vulnerability.

cannabinoid receptor gene, CB2, polymorphism, drug dependence, PCR, HapII RFLP, cannabis, and tramadol