Parkinson Psychosis, Hallucinations, and Delusions

 In Uncategorized

Parkinson’s disease is a neurodegenerative disorder that robs patients of coordination and movement. It has four cardinal motor symptoms; tremor, bradykinesia, rigidity and postural instability. However, all patients have some type of non-motor manifestations. These non-motor symptoms can be as disabling as the motor symptoms. Non motor symptoms include dysautonomia, sleep disturbance, cognition difficulties, mood disorder or psychosis. Progression of motor and non-motor complications increases morbidity, mortality, and caregiver stress. Early recognition and treatment of these complications will improve quality of life.

Psychosis has been estimated to occur in 20-60% of persons living with Parkinson’s disease (PD). Psychosis associated with PD can be difficult to diagnose and treat. There must be a primary diagnosis of idiopathic PD, recurrent episodes, ongoing for longer than 1 month, and occur after the onset of PD. Other causes of psychosis can be due to dementia, metabolic disorders, and medications. PD psychosis is associated with length of dopaminergic drugs, age of onset of disease, and severity of disease. There is an increased risk of psychosis with Hoehn Yahr score>4, MMSE<24, and age>70 years old. Use of anticholinergics can increase risk. Use of donepezil can decrease risk. (1) It is associated with sleep impairment, depression and dementia (2).

Psychosis is an abnormal condition of the mind in which there impaired sense of reality. It usually involves hallucinations or delusions. Hallucinations are perception of visual, auditory, olfactory or tactile stimulus that is not present or real. Visual hallucinations occur in 39% patients with psychosis. Visual illusions are present in 72% of patients (3). This is the visual distortion or perception of movement, form, size or color of an object. This is commonly the misinterpretation of bushes or trees as children or animals outside the house. Another common visual illusion is seeing bugs on the floor. Auditory, olfactory, tactile hallucinations are less common.

The treatment of psychosis can be complicated. It must be individualized and follow a slow, methodical process which includes medication analysis and assessment of PD and comorbid diseases. PD psychosis is triggered by dopamine (D2) receptor activation. Decreasing dopaminergic medications may lead to improve psychosis but decrease motor function (4). The first step is to rule out infection, metabolic or structural abnormality causing the onset of psychosis. The next step is tapering medications such as antispasmodic, anticholinergic, benzodiazepine, muscle relaxants and opioids. Then, gradually tapering dopaminergic medications such as amantadine, selegiline, rasageline, dopamine agonists, and levodopa should be considered. The last step is considering use of atypical antipsychotic medications. There has been an increased risk of death in the elderly with use of antipsychotics.

Atypical antipsychotics use in PD psychosis is effective. The goal of treatment is to minimize dopamine D2 receptor blockade while increasing serotonin 5HT2A antagonism. Clozapine may stimulate D2 receptors and block 5HT2A. It may improve REM sleep as well. It does affect adrenergic, histamine, and cholinergic receptors. It has many side effects and requires frequent blood work. Quetiapine also has minimal D2 receptor blockade with 5HT2A blockade but also affects other receptors. Sedation and orthostatic hypotension are the most common side effects.  Pimavanserin is more selective to 5HT2A receptor. It is the first medication approved for PD psychosis. It can cause QT prolongation and requires decrease dosing in hepatic and renal impairment.

PD psychosis is a common late symptom of Parkinson’s disease. Early diagnosis and treatment is complicated. Treatment must balance the motor and emotional complications of PD. The goal of treatment is to improve quality of life, lessen caregiver stress, and decrease the need for hospitalization.




1 “Trigger medications and patient related risk factors for Parkinson Disease Psychosis requiring anti-psychotic drugs: a retrospective cohort study”, BMC Neurology, 2013; 12: 145.

2 “Cognitive correlates of psychosis in patients with Parkinson’s disease”, Cognitive Neuropsychiatry, 2014; 19(5): 381-398.

3 “Characteristics, correlates, and assessment of psychosis in Parkinson’s Disease without dementia”, Parkinsonism Related Disorders, 2017; 43: 56-60.

4 “12 year population based study of psychosis in Parkinson’s Disease”, Archives of Neurology, 2010; 67(8): 996-1001.

Recent Posts

Leave a Comment