DRD2 and schizophrenia: Brain-derived neurotrophic factor (BDNF), cannabinoid receptor 1 (CNR1), catechol-o-methyl transferase (COMT), protein kinase B also known as AKT1, and dopamine receptor D2 (DRD2) are some of the genes that are at risk of developing schizophrenia after early cannabis exposure; however, the transition rate is meager [18].