DRD2 and schizophrenia: In the last decade, four other genes related to cannabis use and psychosis have been examined, namely, NOS1AP, DRD2, BDNF, and FAAH. First, Husted et al. (2012) demonstrated that the presence of the NOS1AP risk of the schizophrenia genotype did not influence schizophrenia expression associated with cannabis use [70].