If the functional significance of the A2AR-D2R heterodimers can be demonstrated by future studies with direct manipulation of these heterodimers (such as the blocking peptide specifically targeting the A2AR-D2R heterodimers interface; Azdad et al., 2009) in intact animals, the A2AR-D2R heterodimers may represent a novel therapeutic target for controlling abnormal habit formation associated with obsessive compulsive disorders and relapse of drug addiction. This evidence concerns the gene ADORA2A and obsessive-compulsive disorder.