Charles Bonnet Syndrome - LPNI

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Charles Bonnet Syndrome

LPNI Health Topic – December 2021

With advances in medical care and technology, average life expectancy is increasing in many countries. Many diseases and disorders are being cured or controlled, while at the same time more age-related conditions are being experienced. Vision loss such as Age Related Macular Degeneration is common the elderly. It is estimated that about one person in every two with vision loss may experience hallucinations known as Charles Bonnet Syndrome (CBS), but most people are unaware of this condition. Research suggests that many who suffer from CBS do not consult their doctor out of fear and embarrassment, as hallucinations are associated with mental illness.

The cause of CBS is not well understood, but it is thought to be related to the brain continuing to interpret images, although absent, with simple or complex hallucinations. Simple hallucinations include shapes and patterns, while complex hallucinations include images of people, vehicles, animals, and plants. Episodes can range from a few seconds to hours, and may recur over the course of several days to years.

The features of hallucinations can vary from one episode to the next and from person to person, but generally they tend to occur when the person is alone, quiet, and in familiar surroundings. The images may be in colour or black and white; static like a photograph or moving like an event in real life; life sized or reduced in size; realistic (such as animals from the real world) or fantastic (such as mythological monsters); enjoyable like a pleasant dream or nightmarish; meaningless and random or featuring familiar people and places. In most cases, the hallucinations go away as the brain adapts.

A person with CBS has no control over their hallucinations. Issues may arise in everyday life because the hallucinations overlay images of the real world, making it difficult to negotiate everyday tasks such as walking through an unfamiliar environment. Initially the person may not know whether the image is real or not. This can be frightening if, for example, seeing a stranger in the house. Seeing things that are not there is distressing, even if they are pleasant, and may lead to a fear of ‘going mad’ or exhibiting signs of dementia.

Diagnosis of CBS may include medical history, physical and eye examination, as well as medical tests to rule out other pathology such as dementia, mental illness, stroke or metabolic disorders. Treatment differs depending on the impact symptoms have on the person’s life. Some people are taught to block their hallucinations, while others may benefit from antipsychotic medications. Vision therapy moving the eyes up and down or side to side may dissipate the hallucinations.

There is no medical cure for Charles Bonnet Syndrome, although it often resolves after about 12-18 months without treatment. Sometimes, however, the hallucinations do not go away and counselling may be needed for reassurance.

Sylvia Hutt Retired RN

Aberfoyle Park, South Australia