MTARC2 and schizophrenia: Interestingly, the two nominally significant CpG sites (P < 0.05) that overlap between the cannabis-only and the cannabis with tobacco data are located within the MARC2 and CUX1 genes, which both have reported roles in brain function; a SNP in MARC2 has been provisionally associated with the biological response to antipsychotic therapy in schizophrenia patients77, and the CUX1 gene has an established role in neural development78.