To investigate further the roles of CNR1 and CNR2 in the pathophysiology of psychosis and drug-taking behaviors, we examined the association of CNR1 and CNR2 genes with several clinical phenotypes of methamphetamine dependence and psychosis, such as the age at first consumption of methamphetamine, latency to onset of psychosis after abuse, prognosis of psychosis after therapy, spontaneous relapse even without reconsumption of methamphetamine, and multiple substance abuse status, which show individual variation and may in part be regulated genetically. Here, CNR1 is linked to substance abuse.