SLC6A3 and major depressive disorder: (Pirker 2003) (EMA) (Rukavina et al. 2023) In individuals with early stages of PD, dopamine deficiency in posterior putamen has been indicated as a key determinant of the severity of motor deficits (measured using the Unified PD Rating Scale Part III (UPDRS III)), while increasing severity of both anxiety symptoms and depression symptoms (measured using the State-Trait Anxiety Inventory (STAI) and Profile of Mood States Scale (POMS) depression subscale respectively) correlate with decreased DAT availability in the left anterior putamen region.