MAO‐B inhibitors sustain synaptic DA levels by inhibiting its degradation: rasagiline (NCT01382342, Phase IV) effectively improves motor function but has little effect on PD‐associated apathy and other nonmotor symptoms, while safinamide (NCT00643045, Phase III) exhibits excellent safety as an adjunct therapy and is well‐suited for combination with other anti‐PD medications. Here, MAOB is linked to Parkinson disease.