Notably, these genes were not all related to dopaminergic receptors, indicating that development of TRS may occur through multiple pathways.62 A study comparing gene expression among patients with TRS, patients with treatment-responsive schizophrenia, and healthy controls found no difference between the groups with schizophrenia in the expression of 13 candidate genes, including COMT.63 Although there are inconsistencies and variability among the results of some of these highlighted studies, several candidates for the biological mechanisms or subtypes of TRS require further research. The gene discussed is COMT; the disease is schizophrenia.