MAO-B inhibitors such as moclobemide, tranylcypromine, seligiline, and rasagiline (taken alone or in combination with other antidepressants) have been found to be useful in treating depression and anxiety in PD (Steur and Ballering, 1997; Fahn and Chouinard, 1998; Nayak and Henchcliffe, 2008; Korchounov et al., 2012). This evidence concerns the gene MAOB and Parkinson disease.