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. The gene discussed is CUX1; the disease is schizophrenia.