GBA1 and Mental deterioration: We observed an increased LID risk in GBA mutation carriers, in line with reports that GBA mutations are associated with more rapid motor progression,19, 33 earlier age at onset,33, 34, 35 and possibly earlier DBS surgery.36 GBA‐PD is also generally associated with rapid cognitive decline and earlier dementia,19, 33, 34 whereas we found higher baseline MMSE also increased LID risk.