Schizophrenia and the cannabinoid receptor type 1 (CB1): Association studyusing a single-base polymorphism in coding exon 1

Abuse of cannabis is frequent among the young and is suspected to precipita te schizophrenia in vulnerable subjects. Cannabinoid receptor (CB1) is part icularly concentrated in dopamine-modulated areas of the nervous system. An association between an AAT polymorphism of the CB1 gene and intravenous dr ug abuse has been previously reported, but not with schizophrenia. In a Fre nch Caucasian population, we compared the distribution of a single-base pol ymorphism revealed by MspI within the first exon of the CB1 gene in patient s with schizophrenia (n = 102) and ethnic- and gender-matched controls (n = 63). No significant difference was seen in the allele or genotype distribu tion between the whole sample of schizophrenic patients and controls. Howev er, we found a borderline lack of allele g and a significant lack of gg gen otype in the non-substance-abusing patients compared to substance-abusing p atients, the latter being similar to the controls. These results are the fi rst report of an significant association between CB1 receptor and a subtype of schizophrenia. Studies are needed to confirm and further explore the pr ecise role of the cannabinoid system in schizophrenia. (C) 2001 Wiley-Liss, Inc.