COVID Has had many effects that were unexpected, and it actually highlighted issues that lurked in the background for many decades, even centuries. One of these issues is Charles Bonnet Syndrome.

To start at the beginning, this Syndrome was first described by Charles Bonnet almost three hundred years ago. Charles Bonnet noted that his grandfather, a highly respected retired magistrate, saw patterns, figures, birds, and other images that were not there. It is important to note that his grandfather was mentally healthy.

And this is the important point. People with Charles Bonnet Syndrome (CBS) have hallucinations, but they enjoy good mental health i.e. visual hallucinations in psychiatrically normal people who have lost vision.

Besides these two facts, there is little known about the syndrome in the 21st century. However, the Covid pandemic is bringing more evidence to light.

First, until now we believe that the syndrome has been grossly under-reported. Many factors contribute to this. People are terrified of being labelled as mentally ill if they report hallucinations, and we now understand that some individuals may have been erroneously diagnosed with various forms of dementia. In addition, far too many health care professionals are unaware of CBS, and thinking that it occurs very rarely, they relegate it to a back burner. Finally, the diagnostic criteria are often not clarified.

Until now!

If we look at the causes and conditions associated with CBS, it is easy to understand why this condition is receiving more and more attention today.

CBS is associated with:

• Ageing
• Visual loss
• Isolation
• Stress
• Certain medications

However, the past months have highlighted many hitherto unknown facts, and a closer look has given us added insights.

First, CBS is far more widespread than previously believed.

Secondly, all ages can be affected and for example at a UK hospital, it was found that 50% of children admitted with Covid had neurological symptoms that they had never experienced before. (Study sees mysterious Covid-related inflammation leading to hallucinations, confusion … by Tera News, April 16, 2021).

Thirdly, the conditions surrounding the virus, including isolation, have exacerbated the symptoms for most sufferers.

So what, then, is CBS?

Put simply, it is the experience of visual hallucinations in mentally healthy people. To clarify the difference, an hallucination is the perception of an external object when no such object is present, as opposed to a delusion which is being convinced that the hallucinations are real and an illusion is misinterpreting real objects.

Looking at the hallucinations in more detail provides few answers.

• They are varied, and unique to each individual
• Some are simple, taking the form of patterns, blocks, dots, etc.
• Some are very complex, involving inexplicable images
• They may be friendly, funny, hostile, and some are quite terrifying while some could be pleasant
• They may be fleeting or last a few hours
• They rarely persist for a few weeks or months. (There is documentation of a few people experiencing CBS for up to eight years. The pandemic has resulted in reports that both the duration, frequency, and persistence has increased.)

The pathogenesis of CBS is rather unclear. One theory (deafferentation theory) presumes that a reduced visual input to the brain results in the brain attempting to make sense of the fragments that are seen.

The brain then tries to fill the missing gaps with images that are stored in memory or may be produced at the time.

In other words, ageing, vascular changes, sensory deprivation and visual impairment, individually or together, cause abnormal activity in the visual areas of the brain, resulting in hallucinations. However, much research is required to establish the exact causes and effects that CBS produces.

The diagnosis is made when an individual experiences hallucinations, and has sufficient insight to recognise that they are not real.

After a time, it appears that the brain readjusts to the gaps in information and the abnormal firing of neurones decreases.

The management of CBS is based on recognising the situation, explaining the phenomenon clearly to the individual, and reassurance that it is not a mental problem. It is physiological and will pass with time.

Different measures to cope with an episode of hallucinations include:

• change the lighting in the room e.g. if dark, switch a light on and vice versa
• distractions are effective especially if you stimulate other senses
• blink slowly or move your eyes up and down or from side to side
• stare directly at the hallucination
• stand and move around
• practice relaxing, deep breathing exercises

Written by Karen Denton (Education and Advocacy, Retina SA)

More information is available at retinasa.org.za and at charlesbonnetsyndrome.uk