The history of hallucinations in Parkinson’s disease (PD) started to be noticed in the early 19^th century, there was debate about if the symptoms were caused by PD itself, association with dementia, or due to effects of therapies. [1]

The first case of a man who presented with PD and psychosis was detailed by Doctor  Victor Parant in 1883 who determined hallucinations occurred in late-stage PD. Parant cited the publications by Benjamin Ball in 1881 and 1882 that linked PD to depression and cognitive symptoms. During the 20^th century, it was an accepted belief that hallucinations in PD occurred due to dopaminergic treatments or encephalitic infection. However, newer studies suggest that hallucinations may occur as a precursor to PD psychosis (PDP), resulting from the progression of PD, similar to the historical view of Parant. [1][2][3][4]

We reviewed 10 papers on historical notations of PD hallucinations, mental health symptoms beginning from its emergence in the literature  by Benjamin Hall in 1881 and then in  1883 by Victor Parant.

PD hallucinations were first described  in 1883 by Victor Parant  who had a private mental health clinic located in Toulouse, France.[4]  Victor Parant’s publication was the first documentation of dementia, hallucinations and psychosis  associated with PD. It was widely accepted throughout the 20^th century that hallucinations in PD were either due to certain treatments or associated with PD dementia. However around 2005, our thinking evolved as more recent studies demonstrated that hallucinations and PDP may be due to the pathology of PD. [4][5]

PD hallucinations were documented in 1883. This initial report described hallucinations in PD  associated with psychosis and having auditory, visual and paranoid delusions.  The initial publications of Benjamin Ball  in 1881 and 1882 was the first impetus to link PD to mental health conditions.[4] PD hallucinations predated medication interventions.