DRD5 and Hypertension: Despite the association with schizophrenia (Muir et al., 2001), attention-deficit/hyperactive disorder (Daly et al., 1999) and substance abuse (Vanyukov et al., 1998), gene targeting studies revealed that DRD5 knock-out mice develop hypertension, showing increased blood pressure from 3 months of age (Hollon et al., 2002).