OPRM1 and cocaine use disorder: Based on the current hypothesis on the role of the balance of the A2AR-D2R, MOR-DOR, MOR-D2R, and MOR-MOR complexes in the GABA antireward neurons for the development of morphine use disorder the work by Mongi-Bragato and colleagues (Mongi-Bragato et al., 2016; Mongi-Bragato et al., 2018) implies that this balance is of relevance also for cocaine use disorder.