Mental illnesses, especially those of a neurodegenerative nature, affect patients’ brain functions in ways that still continue to surprise the medical and scientific community. This is the case with the psychosis produced by Parkinson’s disease.

Although it is not the most common, on some occasions the dementia that can accompany Parkinson’s disease turns into a psychosis , causing all sorts of symptoms typical of this disease. In this article we will discuss these symptoms and the possible treatments that exist to combat them.

When Parkinson’s Precedes Psychosis

As a general rule, Parkinson’s disease is considered a neurodegenerative condition that is distinguished by causing a range of movement disorders. The most characteristic symptoms of this are those that affect motor function and are manifested by very characteristic tremors, difficulties with walking and problems in initiating movement.

However, in addition to the motor symptoms, this disease is also characterized by symptoms related to cognition and mood. Therefore, it is not unusual for psychotic symptoms associated with Parkinson’s disease to appear in certain cases.

In some Parkinson’s patients, a progressive dementia known as dementia of Lewy bodies appears. These bodies consist of abnormal clumps in the brain of a protein known as synuclein. Although this element is usually found in the substantia nigra region, the spread of Lewy bodies outside of this region has been associated with non-motor symptoms and the development of progressive dementia.

It is estimated that 20-30% of Parkinson’s patients who develop dementia may have psychotic symptoms. However, there are also registered cases of psychosis in the absence of dementia . Finally, as Parkinson’s disease becomes more severe, so does the severity of psychotic symptoms.

Psychotic symptoms usually appear after the years of the illness, especially when it is in its most serious stages. However, there is a possibility that they may appear at any time, even shortly after starting treatment for Parkinson’s.

What are these psychotic symptoms associated with Parkinson’s?

Traditionally, psychosis has been defined as a mental or psychiatric disorder in which the patient experiences some kind of delusions and/or hallucinations of any kind. Furthermore, when this symptomatology appears within the evolution of Parkinson’s disease , the person may also manifest states of confusion.

This psychotic symptomatology is preceded by a series of alterations and changes in sleep patterns , such as REM sleep behavior disorder, which is distinguished by being a parasomnia in which there is a lack of muscle atony in the REM phase. It is also accompanied by strong, sudden movements and by the experience of violent dreams.

Next, we will explain how psychotic symptoms appear in patients with Alzheimer’s disease.

1. Hallucinations

Hallucinations are one of the most characteristic symptoms of psychotic conditions. They cause the person to perceive stimuli that are not really there . In the specific case of Parkinson’s, these hallucinations can be visual, auditory or even tactile.

At the beginning of the appearance of the hallucinations, these can become very frightening for the patient, since they are usually related to the perception of already dead people or extremely strange elements. Unfortunately, the severity of these tends to increase with the development of the disease , causing real states of anxiety and panic in the patient.

2. Delusions

In Parkinson’s patients with psychotic symptoms, the delusions or delusions are often paranoid in nature . The content of these is often related to the idea that he is being watched, persecuted or that one or more people are trying to do him harm of any kind.

3. States of confusion

In states of confusion or confusional symptoms, the patient experiences alterations in consciousness. One of the signs that the patient is beginning to manifest psychotic symptoms is that he tends to experience fluctuations between alert and waking states, problems with concentration and a kind of disconnection from everything around him.

This type of disorganized thinking tends to favor the paranoid ideas mentioned above. In addition, if this happens in elderly patients or in those with comorbidity with other diseases, it can lead to severe delirium.

Is there any treatment?

Before beginning any type of intervention to alleviate the psychotic symptoms of Parkinson’s, the causes that are causing these symptoms must be specifically defined. Usually, these are caused by the antiparkinsonian medication itself ; however, they may also be the consequence of an infection that triggers delirium or the dementia that accompanies Parkinson’s disease.

Once the origin has been determined, the first treatment measures can begin. Since the medication itself is responsible for the appearance of delusions and hallucinations, the first steps to be taken are to adjust the dose of the medication . However, this is a very complicated process, because if you lower the medication too much, the motor symptoms of Parkinson’s can increase dramatically. But if no change is made, the psychotic symptoms will increase.

In the event that psychotic symptoms cannot be reduced by an adjustment in the Parkinson’s medication, the doctor may decide to resort to antipsychotic medication. However, this choice is not without risk either.

Drugs used to treat psychotic symptoms are usually effective because they block dopamine receptors in the limbic areas of the brain. However, they can also block dopamine in brain regions that manage motor functions, such as the striatum, which will lead to more abnormal Parkinson’s-like movements.

Even so, if these psychotic symptoms are severe enough to require the use of medication, the use of typical antipsychotics such as haloperidol is discouraged, with atypical antipsychotics such as clozapine or quetiapine being much more effective and having fewer side effects.

In recent years, a drug has been developed for the treatment of psychotic symptoms in people with Parkinson’s disease and has been approved by the FDA. This drug decreases the psychotic symptoms associated with this disease without worsening the motor symptoms. Known as pimavanserin , this drug influences psychotic symptoms without directly blocking the flow of dopamine. However, this drug is of very recent creation, so time will tell how effective and safe it can be.