The present invention is directed to a combination treatment of an opioid antagonist e.g., naltrexone and a second compound selected from the group consisting of a GABA B agonist, an NMDA antagonist, a serotonin antagonist, and a cannabinoid antagonist is the key to the successful treatment of a brain reward system disorder. A brain reward system, include but are not limited, to pathological gambling, compulsive alcohol consumption, compulsive over-eating and obesity, compulsive smoking, and drug addiction. The compounds and methods of the present invention effectively reduce the cravings, withdrawal symptoms and negative drug side effects associated with a monotherapy. As such, patient compliance is greatly increased, thereby decreasing relapse of a brain reward system disorder.