Charles Bonnet Syndrome – More Common than you Think

You probably haven’t heard of it, yet studies estimate the somewhat mysterious (and often frightening) Charles Bonnet Syndrome (CBS) affects between 0.4 and 30% of the population. Although this often, initially, confusing eye condition can be experienced by people of all ages, it is more prevalent in those aged 70 and over. Researchers believe CBS may be significantly under-reported because those who suffer from it hesitate to talk about symptoms that can have them doubting their own sanity!

Charles Bonnet Syndrome, which was first described in 1760 by the Swiss philosopher of the same name, is a condition characterised by the visual hallucinations experienced by many with partial or complete loss of sight. (The greater the extent of sight loss, the more likely Charles Bonnet Syndrome will be present.)

Technically, the term ‘hallucination’ is used to describe the experience of ‘seeing’ something which doesn’t actually exist.’ It can apply to a number of physical and mental health conditions including bipolar disorder, Alzheimer’s, and Parkinson’s disease. In the case of CBS, scientists speculate the hallucinations are the brain’s response to a deprivation of real-world visual imagery. As a way of compensating for this deprivation, the brain ‘invents’ images in the form of hallucinations.

The hallucinations accompanying CBS can vary widely and be moving or stationary. Some sufferers describe seeing coloured patterns, lights, lines, and flashes. Others see more distinct images including flowers, animals, familiar or unfamiliar faces, dancers, trees, outdoor scenes … the variety is endless. Some who experience ‘pleasant’ images can be intrigued by them, but for others, the hallucinations can be very frightening. Sufferers of CBS have described ‘seeing’ animals sitting in the middle of a busy road, or waking to find ‘a person’ in their room. Some have even thought they are seeing ghosts. Hallucinations of bugs crawling over food can even put a CBS sufferer off their food.

While it can be something of a relief for a CBS sufferer to learn their hallucinations are not the symptom of a mental disorder, a diagnosis of the condition is not the end of the story. This is because CBS is simply the result of whatever it is that caused the vision loss – and the reasons for this can be many. They include cataracts, glaucoma, giant cell arteritis, and stroke. Which is why, although it may feel difficult to approach your GP with hallucinatory symptoms, it is vital you do so at the earliest opportunity. Putting off an appointment with your medical professional out of fear of disclosing your CBS symptoms, can lead to a medical emergency (such as a stroke) that could have otherwise been better managed if dealt with in a timely manner.

As for treating CBS itself, although there is currently no cure, symptoms can often improve over time. This may be because the brain adapts to a deprivation of real-world imagery. It’s also possible sufferers become less aware of the hallucinations even though they are still present. Interestingly, CBS is more common in those who spend time alone than in those who actively socialise, so making an effort to find conversation and join in with groups can help. Reducing stress, having adequate rest, and adjusting light levels in your home can also be used as management tools. Some people with CBS will benefit from brighter light levels while others will find it helpful to reduce light levels.

But perhaps what is most helpful is realising you are not alone with your symptoms, and CBS is not an indication of a mental health issue. Currently, there is no specific CBS support network in New Zealand, but the Australian-based Charles Bonnet Syndrome Foundation can be accessed online. If you are experiencing hallucinations, see your GP immediately.