What is Charles Bonnet Syndrome?
Charles Bonnet syndrome (CBS) is a condition where a person experiences detailed visual hallucinations, usually due to changes in their vision such as vision loss. Hallucinations are experiences involving the apparent perception of something not present. These hallucinations can be caused by problems anywhere in the vision pathway – this includes the optic nerve (which sends visual information from the eyes to the brain), the brain itself, or the eyes.
Charles Bonnet syndrome often goes unnoticed, and is sometimes mistaken for early signs of dementia or psychosis, which are both mental health disorders. This is because patients often don’t realize that what they’re seeing isn’t real, and they typically have little to no control over these hallucinations.
The condition was first described by the Swiss scientist Charles Bonnet in 1760. Bonnet recognized the condition in his grandfather, who started experiencing visual hallucinations after cataract surgery. Although his grandfather’s vision initially improved after the surgery, his sight deteriorated later on, and he started having hallucinations. He did not have any mental health disorders.
The main factors contributing to Charles Bonnet syndrome are believed to be cognitive malfunction (problems with thinking abilities), feeling isolated from others, and sensory deprivation (being cut off from sensory experiences, like seeing or hearing). People often don’t realize they have the condition until they’re older. This may be because they’re worried about being seen as having mental health difficulties or admitting they’re having hallucinations.
Some people who recognise the hallucinations as unreal can become depressed, fearing they’re going insane. Doctors need to take an in-depth look at a person’s medical history to rule out the possibility that the hallucinations are being caused by something else. Hallucinations may stop on their own over time or may improve if a person’s sight gets better or their feeling of social isolation eases.
Medication used to treat seizures (anticonvulsants) have been found to help stop hallucinations, but there isn’t a single, specific medicine for Charles Bonnet syndrome. The best way to manage the condition is for eye doctors and other physicians to be aware of it so it can be properly diagnosed.
Theories about what causes Charles Bonnet syndrome range from “phantom vision” (occurring due to sensory deprivation) and a connection to dream states, to the role of social isolation, aging, psychological influences, and theories on brain activity. However, there isn’t a definitive explanation for CBS yet.
What Causes Charles Bonnet Syndrome?
Charles Bonnet Syndrome, or CBS, can result from many things that affect the visual pathway – this is everything involved in seeing, from the parts of the brain that process vision down to the eyes themselves. However, it doesn’t happen with blindness that a person is born with.
Common reasons for CBS include:
* Diabetic retinopathy (eye damage from diabetes)
* Age-related macular degeneration (vision loss due to aging)
* Cerebral infarctions (type of stroke)
* Glaucoma (vision loss from damage to the optic nerve)
* Macular degeneration (loss of central vision)
* Cataract (clouding in the eye’s lens)
* High myopia (severe nearsightedness)
* Retinitis Pigmentosa (breakdown and loss of cells in the retina)
* Optic Neuritis (inflammation damaging the optic nerve)
* Retinal vein occlusion (blockage of the small veins that carry blood away from the retina)
* Central retinal arterial occlusion (blockage of the artery carrying blood to the retina)
* Occipital stroke (stroke in the part of the brain involved with vision)
* Temporal arteritis (inflammation and damage to blood vessels that supply the head area)
One theory that tries to explain CBS is known as the phantom limb pain theory. This theory explains why amputees might still feel pain in a limb that’s been removed – something that might also happen in CBS. Even though they can’t see, people with CBS might still sense that they can.
Risk Factors and Frequency for Charles Bonnet Syndrome
Charles Bonnet Syndrome (CBS) is more common than people think, but the exact number of people affected is still being studied. Some research suggests anywhere from 1% to 10% of people could be affected. A large study found that about 0.5% of their sample had CBS. This included people with poor eyesight, elderly people, and those who were both elderly and had poor eyesight. Further research has shown that CBS is even more common in people with severe vision loss.
This syndrome can affect anyone of any age, but it is more common in older people, typically between the ages of 70 and 85. This is when health issues that cause vision loss are more likely to happen. Despite CBS being more common than people think, it’s often not reported because people fear they will be diagnosed with a mental health problem. For example, in one study only 12% of patients at a retinal clinic knew about CBS. Another study found that only 11 to 15% of older people with vision problems reported having visual hallucinations, a key symptom of CBS.
- The occurrence of Charles Bonnet Syndrome (CBS) ranges from 1% to 10%, as suggested by various studies.
- A larger study found that CBS was prevalent in 0.5% of their total sample, with higher rates among those with lower visual acuity and older age.
- CBS can affect individuals of all ages but is usually more common among older individuals aged 70 to 85.
- Despite its prevalence, CBS is often under-reported due to fears of being diagnosed with a mental health disorder.
- Recorded knowledge about CBS is minimal with only 12% of patients in a retinal clinic aware of the syndrome, and only between 11% to 15% of older individuals with impaired vision reporting the occurrence of visual hallucinations.
- Most often, CBS is reported in people above 70 years old and the syndrome is also observed in children with rapid loss of vision.
- Ideally, CBS is more common in males, but some studies have found it to be more common in females or equally divided between the genders.
Signs and Symptoms of Charles Bonnet Syndrome
Charles Bonnet Syndrome (CBS) is a condition where people with vision loss experience visual hallucinations. These hallucinations can start from light flashes or simple shapes to complex scenes with detailed images. The hallucinations are usually colorful and can be stationary or moving. People with this syndrome often report these hallucinations as distressing even though they know they are not real. It is important to note that CBS doesn’t involve sensory or auditory hallucinations – the hallucinations only affect sight.
These hallucinations can start at different times depending on the cause of the vision loss. For instance, people with a slowly progressing eye disease usually start to have hallucinations about a year after they experience severe visual impairment or complete vision loss. On the other hand, individuals with sudden vision loss due to damage in the optic nerve or brain report hallucinations within hours or days of the vision loss. However, they can also start seeing hallucinations months after the event that caused the vision loss.
The hallucinations seen in CBS can be simple or complex. Simple hallucinations might include patterns, lines, or shapes. Complex hallucinations could contain clear and intricate images of people, faces, animals, and objects amongst others. Regardless of the type of hallucination, the images are usually clearer and more vivid than the person’s actual residual vision.
- Simple hallucinations
- Complex hallucinations
- Vivid and clear images
In addition to the hallucinations, a person’s existing vision loss needs to be assessed. An eye examination can identify things like glaucoma, cataracts, or damage in the retina or optic nerve. Neurological deficits usually seen after a stroke can also be present as the vision pathways in the brain might be damaged and hence, contribute to CBS.
A study showed that 38% of the participants found the hallucinations frightening and unsettling when they first started. However, over time, the emotional response to the hallucinations decreased to 8%. Most people, about 60%, reported that the hallucinations didn’t affect their lives, while 33% said it had a negative impact, and 7% said it improved their lives. Despite CBS often being defined by complex visual hallucinations, many patients typically present simpler visual hallucinations.
It’s also important to note that individuals with CBS experience these hallucinations when they are awake and alert. They do not have dementia, and their mental functions are preserved. Their ability to think, reason, judge, and apply knowledge remains intact.
Testing for Charles Bonnet Syndrome
The first step in checking for Charles Bonnet Syndrome (CBS) is to look for signs of disorders that affect the brain’s thinking, understanding, learning, and remembering capacities, as well as signs of problems with the nervous system. This is done through a thorough check-up of the nervous system. Other tests like brain scans, electroencephalography (EEG, a test that measures the electrical activity of the brain), lab tests, and genetic testing may also be required depending on what neurological conditions are suspected.
A review of the person’s medications will also be undertaken to see if any of them might be causing hallucinations. Some common medications that aren’t primarily used for mental health conditions but have been known to cause hallucinations include heart medications (beta-blockers), medications that lower blood pressure (angiotensin-converting enzyme inhibitors), heartburn medications (cimetidine, ranitidine), a medication used to treat erectile dysfunction (sildenafil), and various antibiotics. Over-the-counter medications, including ephedrine and synthetic cannabinoids, are even more common culprits.
Mental health medications and substances that are often misused also need to be considered as potential causes of hallucinations. Once it’s been confirmed that hallucinations aren’t due to a neurological condition or medication, the next step is to confirm whether the person has a vision impairment or loss. This is done through an eye examination and tests to evaluate the person’s field of vision.
Brain scans may also be performed on people who have unremarkable eye exams despite their impaired or lost vision. To sum up, a diagnosis of CBS can be made if a person is experiencing visual hallucinations only, if there’s no evidence of neurological abnormalities, and if the person has a confirmed vision impairment or loss.
Treatment Options for Charles Bonnet Syndrome
If you are experiencing only mild symptoms of Charles Bonnet Syndrome (CBS), which is a condition that can cause people to see things that are not real (hallucinations), sometimes engaging in some reassurance can be all you need for your condition. However, when symptoms are more severe, behavioral methods and medications may be needed to manage the hallucinations. For example, some people find it helpful to blink or deliberately shift their eyes to a new object when they have a hallucination.
One of the most important aspects of managing CBS is simply being aware of the condition and having empathy: a caring physician can make a big difference for people living with CBS.
In cases where symptoms are very troubling or constant, medications may be used. These can vary and your doctor may suggest something that best suits your individual condition. Some of the medications that might be used include antipsychotics with generally safe side effect profiles, especially preferred for older adults who this condition often affects. Other frequently used medications are cholinesterase inhibitors (these increase the levels of certain chemicals in the brain that nerves use to communicate with each other), and antiepileptics (these control the electrical activity in the brain that leads to seizures). Moreover, some antidepressants and medications that improve the movement of food through the stomach and intestines have also been found to be promising in treating CBS.
Psychological therapy can also be used to manage CBS. This might include methods like hypnosis, relaxation exercises, or cognitive remodeling (a technique that helps to change and manage thoughts that might be causing problems). These techniques can all help to reduce the distress caused by the visual hallucinations that come with CBS.
Many individuals with CBS may feel anxious because they do not fully understand their condition, so reassurance is a big part of treatment. It can be comforting to learn that the hallucinations are due to CBS and not a sign of mental illness, and that they are not harmful. Further interventions might not be necessary for patients who are cognitively intact, but those with dementia might be difficult to reassure due to their impaired understanding and the distressing nature of their visual loss.
Finally, optimizing visual function, or making the most of the vision that you have, can be one of the best treatments for CBS. However, correcting visual deficits may not always be possible, especially in older adults. In some cases, corrective glasses or visual aids might be helpful, and in other instances, surgical removal of cataracts could improve vision.
What else can Charles Bonnet Syndrome be?
When it comes to diagnosing conditions that involve visual hallucinations, doctors may need to consider a range of potential causes. These include:
- Narcolepsy (a sleep disorder)
- Peduncular hallucinosis (hallucinations caused by brain lesions)
- Hallucinations induced by Levodopa (a medication)
- Hypnagogic hallucinations (hallucinations that occur just before sleep)
- Migraine coma (loss of consciousness following a severe migraine)
- Schizophrenia (a severe mental disorder)
- Epileptic seizures
- Dementia
- Migraine aura (sensory disturbances preceding a migraine)
- Neurodegenerative diseases like Parkinson’s, Alzheimer’s and Lewy body dementia
- Metabolic encephalopathy (brain disease caused by things like drugs, alcohol withdrawal, or delirium).
These conditions can be distinguished from Charles Bonnet Syndrome (CBS) due to the presence of visual deficits and the absence of neurological deficits in CBS. Also, CBS does not involve auditory or sensory-associated hallucinations, unlike many of these other conditions.
What to expect with Charles Bonnet Syndrome
Charles Bonnet syndrome (CBS), which affects a person’s vision, can have quite a varied prognosis. The outcome mostly depends on what initially led to the person’s vision impairment or loss. For example, if the vision problem is associated with an ongoing eye disease, a person could have symptoms for several years.
One research study found that 75% of people with a specific type of eye disease known as “macular disease” experienced hallucinations for at least five years or more. Conversely, if the vision impairment can be quickly fixed, as is often the case with cataracts, the person’s prognosis is typically better.
However, the symptoms of CBS can also fluctuate. For example, when the vision impairment progresses slowly or remains stable, the hallucinations may come and go. This fluctuating course of symptoms is often observed in individuals affected by CVAs, or “cerebrovascular accidents,” which is a medical term for stroke. It’s not unheard of for these strokes sufferers to have hallucinations that last from a few weeks to a few days.
Lastly, apart from the vision-related hallucinations, CBS has also been linked to dementia. In another study, it was found that 26% of individuals with CBS developed dementia within an average timespan of around 33 months.
Possible Complications When Diagnosed with Charles Bonnet Syndrome
Charles Bonnet Syndrome, or CBS, is typically seen as a temporary health problem. It’s not generally linked to severe negative effects or complications, aside from an increase in hallucinations. The complications seen with CBS are mostly related to the psychological impact of the hallucinations that patients experience.
Many patients do not tell medical professionals or their family about these hallucinations, which can lead them to believe they are developing a mental illness. A 2014 study provides evidence for this, revealing that about a third of those suffering from CBS feel emotional distress due to their hallucinations.
Common Issues:
- Increasing in hallucinations
- Psychological impact of these hallucinations
- Patients may believe they are developing a mental illness
- About 32% of patients with CBS feel emotional distress because of their hallucinations
Preventing Charles Bonnet Syndrome
The main ways to prevent and manage Charles Bonnet Syndrome (CBS), a condition where people with vision loss have visual hallucinations, are educating the patient and asking them about any visual hallucinations they may have. It’s important that patients are educated about CBS before they start experiencing hallucinations. Many patients with CBS don’t report their hallucinations because they’re afraid of being seen as mentally ill.
Research has shown that if patients learn about CBS before hallucinations start, this knowledge can reduce unwanted symptoms like fear or hallucinations so strong they disrupt daily life. If a patient does report hallucinations and is diagnosed with CBS, it’s crucial to reassure the patient that CBS is mostly temporary and not related to dementia or mental illness.
