What are the medical causes of hallucinations?

From the Guidelines

Medical Causes of Hallucinations

Hallucinations can be caused by various medical conditions, including neurological disorders such as Parkinson's disease, where dopaminergic medications like levodopa (100-200mg tid) and pramipexole (0.125-1.5mg tid) can induce hallucinations in up to 40% of patients after prolonged use 1. Certain antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) like fluoxetine (20-80mg qd) and sertraline (50-200mg qd), can also cause hallucinations, particularly in elderly patients or those with a history of psychotic disorders 1. Additionally, hallucinations can be a side effect of anticholinergic medications like benztropine (1-2mg bid) and trihexyphenidyl (2-5mg tid), which are commonly used to treat extrapyramidal symptoms 1.

Other Medical Conditions

Other medical conditions that can cause hallucinations include:

• Delirium, which can be caused by underlying medical conditions, substance use, or mental disorders 1
• Dementia, including dementia with Lewy bodies and Alzheimer's disease, which can cause hallucinations in up to 80% of patients 1
• Psychiatric disorders, such as schizophrenia, bipolar disorder, and schizoaffective disorder, which can cause hallucinations as a primary symptom 1
• Neurological disorders, such as frontotemporal dementia, which can cause hallucinations in up to 25% of patients 1
• Vision loss, which can cause Charles Bonnet syndrome (CBS) hallucinations in patients with reduced visual acuity, contrast sensitivity, or visual field loss 1

Key Points

• Hallucinations can be caused by various medical conditions, including neurological disorders, psychiatric disorders, and vision loss
• Certain medications, such as dopaminergic medications, antidepressants, and anticholinergic medications, can induce hallucinations as a side effect
• Delirium and dementia are common causes of hallucinations in elderly patients
• A thorough medical evaluation is necessary to determine the underlying cause of hallucinations and provide appropriate treatment.

From the FDA Drug Label

Hallucinations were observed in 9% (35 of 388) of patients receiving pramipexole dihydrochloride tablets, compared with 2.6% (6 of 235) of patients receiving placebo. Hallucinations and psychotic-like behavior have been reported with dopaminergic medications. Visual hallucinations have been reported occasionally.

The medical causes of hallucinations include:

• Dopaminergic medications, such as pramipexole and levodopa, which can cause hallucinations as a side effect 2, 3
• Neuroleptic drugs, such as phenothiazines, which can cause extrapyramidal disorders and intensify mental symptoms, including hallucinations 4
• Age, which appears to increase the risk of hallucinations, particularly in patients older than 65 years 2
• Other medications, such as antiparkinsonian drugs, which can precipitate a toxic psychosis in susceptible patients 4

From the Research

Medical Causes of Hallucinations

Hallucinations can be caused by various medical conditions, including:

• Biological factors, such as schizophrenia, HIV, and hyperammonemia 5
• Neurological factors, such as Parkinson's disease, Lewy body dementia, and brain tumors 5, 6, 7
• Ophthalmological factors, such as eye conditions that affect vision 5
• Environmental factors, such as substance use and sleep disturbances 5, 8
• Psychological factors, such as delirium and psychosis 5, 9

Specific Medical Conditions Associated with Hallucinations

Some specific medical conditions that can cause hallucinations include:

• Parkinson's disease, which can cause visual hallucinations in up to 40% of patients 6
• Lewy body dementia, which can cause visual hallucinations and is often associated with Parkinson's disease 5, 6
• Schizophrenia, which is a psychiatric condition that can cause hallucinations, including auditory and visual hallucinations 5, 9
• Sleep disorders, such as REM sleep behavior disorder, which can cause hallucinations and is often associated with Parkinson's disease 8

Treatment and Management of Hallucinations

The treatment and management of hallucinations depend on the underlying cause and can include:

• Reducing or changing medications that may be contributing to the hallucinations, such as antiparkinsonian agents 6, 7
• Using atypical antipsychotics, such as clozapine or quetiapine, to manage hallucinations and psychosis 6
• Treating underlying medical conditions, such as sleep disorders or ophthalmological conditions, that may be contributing to the hallucinations 5, 8
• Providing supportive care and therapy to help manage symptoms and improve quality of life 9