COMT and schizophrenia: Given that the relationships between antipsychotic drugs and dopaminergic/serotonergic genes expressions (COMT, 5-HTR2A, and SLC6A4) in schizophrenia remain inconclusive, it is necessary to elucidate the mechanisms of antipsychotic drugs implicated in dopaminergic/serotonergic genes expressions before any final conclusions to be made.