ABSTRACT
Parkinson’s disease (PD) is a neurologic syndrome defined by a triad of motor
symptoms. However, the frequent co-occurrence of cognitive, affective, and
other neurobehavioral disturbance suggests a neuropsychiatric condition with
highly varied symptoms. Depression and anxiety disorders, cognitive impair-
ment, and psychosis have long been recognized in some individuals diagnosed
with PD (1). Other common, but less well studied, psychiatric manifestations
include apathy (2), impulse control disorders (ICDs) (a.k.a., hedonistic home-
ostatic dysregulation, dopamine dysregulation syndrome, or compulsive
behavior) (3), disorders of sleep and wakefulness (4), and pseudobulbar affect.
