In addition, animal studies showed the beneficial impact of some DRD4 antagonists to attenuate or reverse the rewarding effects of cocaine and methamphetamine (Ukai and Mitsunaga 2005; Yan et al. 2004), morphine-induced withdrawal syndrome (Mamiya et al 2004), and nicotine reinstatement (Yan et al. 2012). The gene discussed is DRD4; the disease is substance withdrawal syndrome.