2-fold increased risk for developing schizophrenia and related disorders (7,8,51–53). The significant commorbidity between cannabis use and schizophrenia may be attributable in part to a shared underlying genetic component for CaD and schizophrenia. Second, the neurobiology of CaD and schizophrenia overlap; for example, the mesolimbic pathway is heavily implicated in the neurobiology of CaD (and other substance dependence) and schizophrenia (58, 59). Third, animal studies have provided evidence supporting the role of NRG1 in CaD. NRG1 heterozygous mice have increased sensitivity to the acute neurobehavioral effects of cannabinoids (60, 61); NRG1 modulates the development of tolerance to cannabinoids in mice (62).
