Comprehensive identification of delusions and olfactory, tactile, gustatory, and minor hallucinations in Parkinson's disease psychosis.

INTRODUCTION: Psychotic symptoms are underdiagnosed in Parkinson's disease (PD), and there is a need for a comprehensive PD psychosis rating scale. METHODS: Cross-sectional analysis of 199 consecutive PD outpatients. After a routine clinical visit that included the Unified Parkinson's Disease Rating Scale (UPDRS) and Non-Motor Symptoms Questionnaire (NMS-Quest), subjects completed the enhanced Scale for the Assessment of Positive Symptoms in PD (eSAPS-PD), a structured clinical interview that included the standard SAPS-PD with additional prompts for delusions and olfactory, gustatory, and minor hallucinations. Based on the combined results of these assessments, subjects were categorized as having major psychotic symptoms (hallucinations or delusions; PDP-major), isolated minor psychotic symptoms (passage hallucinations, presence hallucinations, or illusions; PDP-minor), or no psychotic symptoms (PD-controls). RESULTS: We identified 58 subjects (29%) with psychotic symptoms, including 28 (14%) with major psychotic symptoms and 30 (15%) with isolated minor psychotic symptoms. Hallucinations were present in 56 subjects (28%); most commonly visual (24%, of which 21% were minor only), followed by olfactory (6%), tactile (4%), auditory (2%), and gustatory (1%). The eSAPS-PD detected psychotic symptoms in more subjects (n = 55, 28%) than all other assessments combined (clinical visit, UPDRS part 1, and NMS-Quest) (n = 22, 11%). Compared with PD-controls, PDP-minor subjects had a higher burden of other non-motor symptoms on the Non-Motor Symptoms Scale (37 [27-51] vs. 18 [9-36], p < 0.001) and lower quality of life scores on the PD Quality of Life Questionnaire (138 [125-151] vs. 149 [137-165], p = 0.01). CONCLUSION: The eSAPS-PD can markedly improve detection of psychotic symptoms in PD.