FIG. 1.

Participant recruitment, exclusions and total followed over 4 years. NPI = neuropsychiatric inventory; PD = Parkinson's disease; PDD = participants who met level II criteria for Parkinson's disease with dementia; PD‐MCI = participants who met level II criteria for Parkinson's disease with mild cognitive impairment; PD‐N = the remaining participants who did not meet criteria for PDD or PD‐MCI were classified as having normal cognition.^a Assessments were conducted at baseline and then again every 1 to 2 years subsequently; participants with dementia were not followed further.