The cannabinoid receptor gene (CNR1) is not affected in German i.v. drug users

The aim of the study was to investigate a possible contribution of the cann abinoid receptor gene (CNR1) to the development of i.v. drug addiction. All ele and genotype frequencies of a previously associated flanking tripler re peat polymorphism were compared between patients and controls, and the whol e coding region of the CNR1 gene of all patients were screened for presence of mutations. The study took place at the Addiction Treatment Unit of the Mmedical School Hannover, and two outpatients' departments in Hannover, Ger many. Forty German unrelated opioid addicts (27 males and 13 females; mean age 37.9 years; range 16-53 years), look part, all of them satisfying ICD-1 0 and DSM-IV diagnostic criteria for opioid dependence and 81 age- and sex- matched controls (German blood donors). Measurements used were lengths of a lleles, genotyping and single strand conformation polymorphism (SSCP) analy sis. Neither the greater than or equal to5 alleles of the extragenic triple r repeat (AAT) marker nor the alleles of an intragenic biallelic CNR1 polym orphism (1359G/A) were associated with i.v. drug use in our study group. In addition, we did not detect any sequence variation within the CNR1 gene wh ich could confer susceptibility to i.v. drug abuse. In contrast to previous investigations, we found no evidence for an involvement of the CNR1 gene i n i.v. drug addiction.