Hallucinations in schizophrenia and Parkinson's disease: an analysis of ă sensory modalities involved and the repercussion on patients

Hallucinations have been described in various clinical populations, but ă they are neither disorder nor disease specific. In schizophrenia ă patients, hallucinations are hallmark symptoms and auditory ones are ă described as the more frequent. In Parkinson's disease, the descriptions ă of hallucination modalities are sparse, but the hallucinations do tend ă to have less negative consequences. Our study aims to explore the ă phenomenology of hallucinations in both hallucinating schizophrenia ă patients and Parkinson's disease patients using the Psycho-Sensory ă hAllucinations Scale (PSAS). The main objective is to describe the ă phenomena of these clinical symptoms in those two specific populations. ă Each hallucinatory sensory modality significantly differed between ă Parkinson's disease and schizophrenia patients. Auditory, ă olfactory/gustatory and coenesthetic hallucinations were more frequent ă in schizophrenia than visual hallucinations. The guardian angel item, ă usually not explored in schizophrenia, was described by 46% of these ă patients. The combination of auditory and visual hallucinations was the ă most frequent for both Parkinson's disease and schizophrenia. The ă repercussion index summing characteristics of each hallucination ă (frequency, duration, negative aspects, conviction, impact, control and ă sound intensity) was always higher for schizophrenia. A broader view ă including widespread characteristics and interdisciplinary works must be ă encouraged to better understand the complexity of the process involved ă in hallucinations.