No, but it commonly does. Parkinson’s disease affects about 0.5 percent of 65-year-olds and as many as 3 percent of 85-year-olds. Symptoms of mild neurocognitive disorder often develop relatively early in the disease’s lengthy course, and as many as 75 percent of Parkinson’s patients will eventually develop symptoms of major NCD. In such patients, the symptoms are most likely to develop gradually and to include, along with cognitive deficits, apathy, depressed mood, delusions, personality changes, rapid eye movement sleep behavior disorder, excessive daytime sleepiness, and, often, hallucinations.