The PD-MH group had higher percentage of levodopa and dopamine-receptor agonist use than the PD-NH group (P = 0.013, 0.042), while the use of monoamine oxidase-B (MAO-B) inhibitors, catechol-O-methyltransferase (COMT) inhibitors, amantadine, and benzhexol did not differ between the two. The gene discussed is COMT; the disease is Parkinson disease.