Table 1.

Apathy/anhedonia composite measure

MDS-UPDRS part I, item 1.5:	Over the past week, have you felt indifferent to doing activities or being with people? Scale 0–4 (normal–severe)
GDS item 2:	Have you dropped many of your activities or interests? Scale yes (1)/no (0)
GDS item 9:	Do you prefer to stay at home, rather than going out and doing new things? Scale yes (1)/no (0)
GDS item 13:	Do you feel full of energy? Scale yes (0)/no (1)

GDS, Geriatric Depression Scale; MDS, Movement Disorder Society; UPDRS, Unified Parkinson’s Disease Rating Scale.