“The CB1 receptor is encoded by the CNR1 gene (6q14–q15), which is known to carry a nine-allele microsatellite polymorphism containing repeats of a single trinucleotide, ATT, which localizes to the 3’UTR of the gene and has been related to drug dependency states in Caucasian populations.
Moreover, a link has been found between this polymorphism and the properties of the event-related wave p300, some studies having suggested that p300 variations might function as a marker for an underlying, hereditary, predisposition to alcoholism.
Moreover, a direct relationship has been found between p300 wave fluctuations and attention deficit/hyperactivity disorder (ADHD). In recent years, the relationship between ADHD and addictions has been stressed. ADHD has been linked to the malfunctioning of catecholaminergic systems, which also play a fundamental role in the brain’s rewarding system.
These data suggest that the link between the cannabinoid system and the p300 wave could be related to some aspects of ADHD.
In this study, we found a quantitative relationship between the largest-sized alleles of the CNR1 gene and the presence of ADHD during childhood in Spanish male alcoholic patients…
To the best of our knowledge, this is the first study relating the CNR1-gene polymorphisms with ADHD in alcoholic patients.
These data are consistent with the fact that the cannabinoid system is known to affect dopaminergic transmission, with the malfunctioning of the dopaminergic system being regarded as a potential physiopathological cause of ADHD. Further studies are needed to determine the functional basis of the observed association.”