Delusions are challenging non-motor symptoms of Parkinson’s Disease (PD) involving a fixed, false belief that a person holds firmly, even when presented with clear evidence to the contrary. These symptoms, grouped with hallucinations as Parkinson’s Disease psychosis, affect an estimated 20 to 40% of patients over the course of the disease. While less common than other psychotic symptoms, delusions often emerge in advanced stages of PD and can cause substantial distress and caregiver burden.
Differentiating Parkinson’s Delusions from Hallucinations
Parkinson’s psychosis includes both hallucinations and delusions, but they are distinct experiences. A hallucination is a sensory perception where a person sees, hears, or feels something that is not actually present. The most frequent type is a visual hallucination, often involving non-threatening images of people or small animals.
A delusion, by contrast, is a false belief rather than a false perception. Common themes include paranoia, such as believing a partner is unfaithful or that family members are attempting to steal money. Delusions are generally more complex and disruptive than hallucinations. Because the person fully believes the false scenario is real, these symptoms present greater challenges in management and carry a higher risk of behavioral issues.
Factors Contributing to Delusions in Parkinson’s
Delusions are often linked to factors related to both treatment and disease progression. Dopaminergic medications, such as levodopa and dopamine agonists, are prescribed to increase dopamine levels to manage motor symptoms. However, this increased dopamine activity can inadvertently contribute to emotional and behavioral changes, including psychosis.
The disease itself plays a role, as neurochemical changes occur in the brain over time, involving an imbalance of neurotransmitters like dopamine and serotonin. Delusions are often associated with the progression of cognitive impairment, and their presence may indicate the onset of Parkinson’s disease dementia.
External and temporary factors can also trigger or worsen delusional thoughts, making them suddenly more pronounced. These factors include intercurrent medical illnesses, such as a urinary tract infection or pneumonia, which can cause delirium and confusion. Other contributors are dehydration, severe constipation, and poor sleep hygiene or sleep deprivation.
Caregiver Strategies for De-escalation and Safety
When a person with PD is experiencing a delusion, caregivers should avoid direct confrontation or argument. Challenging the fixed, false belief will likely increase the person’s distress, agitation, and resistance. Instead, focus on validating the feeling or emotion behind the delusion, acknowledging that the person is upset or afraid.
A strategy known as redirection can gently shift the person’s focus away from the delusional topic. This might involve suggesting a different activity, moving to another room, or starting a simple, engaging conversation. Speaking in a calm, gentle, and reassuring tone helps to de-escalate rising anxiety.
Caregivers must also ensure the environment is safe, especially if the delusion involves accusations of theft or fear of harm, which can sometimes lead to aggression or self-protective behavior. Remove any objects that could be used to cause injury during an agitated state. Maintaining a predictable daily routine and consistent sleep schedule can also help reduce triggers for confusion.
If the delusions are associated with thoughts of self-harm or aggression toward others, immediate professional help must be sought to ensure the safety of everyone involved. Caregivers should also be mindful of their own well-being and seek support, as managing delusions can be emotionally exhausting.
Medical Approaches to Managing Psychosis
When behavioral and environmental strategies are insufficient, medical intervention becomes necessary and should be discussed promptly with a neurologist. The physician will first conduct a comprehensive review of all medications. They may attempt to gradually reduce the dosage of dopaminergic medications, such as dopamine agonists, as these frequently contribute to psychosis.
The goal of medication adjustment is to find a balance where psychotic symptoms improve without significantly worsening the patient’s motor function. If reducing PD medications is not feasible or fails to resolve the delusions, specific anti-psychotic medications may be introduced.
Pimavanserin is approved by the U.S. Food and Drug Administration for treating hallucinations and delusions associated with PD psychosis. This medication works on serotonin receptors and does not worsen motor symptoms, which is a risk with many older antipsychotics. Other antipsychotics considered relatively safe for PD patients include quetiapine and clozapine, though first-generation antipsychotics are generally avoided due to the high risk of severely exacerbating parkinsonism.