Hallucinations are where someone sees, hears, smells, tastes or feels things that don't exist outside their mind. See your GP straight away if you're experiencing hallucinations and you're worried about them.
About hallucinations and hearing voices
Hallucinations are common in people withschizophrenia, and are usually experienced as hearing voices.
Hallucinationscan befrightening, but there's usually an identifiable cause. For example, they can occuras a result of:
- taking illegaldrugsoralcohol
- a mental illness, such asschizophreniaordementia
- a progressive neurological condition, such asAlzheimer's disease orParkinson's disease
- loss of visioncaused by a condition such asmacular degeneration– this is known asCharles Bonnet syndrome
Read more about the types and causes of hallucinations in sections below.
When to see your GP
See your GP straight away if you're experiencing hallucinations and you're worried about them.
Hallucinations can make you feel nervous, paranoid and frightened, soit's important to be with someone you can trust.
Types of hallucinations
The following information explains the typical types of hallucinations, including why they occur and what you can do. It covers:
- hearing voices
- drug-induced hallucinations
- hallucinationsand sleep
- hallucinations in children with a fever
- Charles Bonnet syndrome
- hallucinations in older people with delirium
Hallucinations can also occur as a result of extreme tiredness or recentbereavement. These and otherrarer causes aren't covered here.
Hearing voices
Hearing voices in the mind is the most common type of hallucination in people with mental health conditions such as schizophrenia.
The voices can be critical, complimentary or neutral. They may make potentially harmful commands or engage the person in conversation. They may give a running commentary on the person's actions.
Hearing voices is a well-recognised symptom of schizophrenia, dementia or bipolar disorder, but can be unrelated to mental illness.
Theexperience is usually very distressing, but it's not always negative. Some people who hear voices are able to live with them and get used to them, or may consider them a part of their life.
It's not uncommon for recently bereaved people to hear voices. This may sometimes be the voice of their loved one.
Practical advice
If you're hearing voices, discuss any concerns you have with your GP. If necessary, they'll refer you to a psychiatrist. This is important as it is to find out whether you have a serious mental illness.
It's important to be thoroughly assessed and treated early. If your voices are due to schizophrenia, the earlier your treatment is started, the better the outcome.
You may also find the following advice helpful:
- talk to other voice hearers, see more useful links section below
- be open to discussing your voices
- try to understand where the voices come from, why and what triggers them
Drug-induced hallucinations
Illegal drugs and alcohol
People can experience hallucinations when they're high on illegal drugs such as amphetamines, cocaine, LSD or ecstasy. They can also occur during withdrawal from alcohol or drugs if you suddenly stop taking them.
Drug-induced hallucinations are usually visual, but they may affect other senses. They can include flashes of light or abstract shapes, or they may take the form of an animal or person. More often, visual distortions occur that alter the person's perception of the world around them.
The hallucinations can occur on their own or as a part of drug-inducedpsychosis. After long-term drug use, they may cause schizophrenia.
Some people take cannabis to "calm themselves" and relieve their psychotic symptoms, without realising that in the longer term, the cannabis makes the psychosis worse.
Heavy alcohol usecan also lead to psychotic states, hallucinations and dementia.
Medication
Various prescription medicines can occasionally cause hallucinations. Elderly people may be at particular risk.
Hallucinations caused by medication can be dose-related and they usually stop when you stop taking the medicine.
Never stop taking a medication without speaking to your doctor first and, if necessary, after being assessed by a psychiatrist.
Speak to your GP about how the medication is affecting you, so you can discuss the possibility of switching to another medicine.
Hallucinations and sleep
It's common for people to experience hallucinations just as they're falling asleep (hypnagogic), or as they start to wake up (hypnopompic).
The hallucination may take the form of sounds, or the person may see things that don't exist, such as moving objects, or a formed image, such as a person (the person may think they've seen a ghost).
Hypnagogic and hypnopompic hallucinations are particularly common in people withnarcolepsy. They can also occur in people without narcolepsy or any disorder.
They're essentially like dreams, and in themselves are nothing to worry about.
Hallucinations in children with a fever
Hallucinations can sometimes occur in children who are ill with a fever. Call your GP if your child is unwell with a body temperatureof 38C (100.4F) or above and you think they're hallucinating.
In the meantime, stay calm, keep your child cool and reassure them.
Encourage them to drink plenty of fluids and give themparacetamoloribuprofen. You should always read the patient information leaflet to find out the correct dose and frequency for your child’s age, and check they're not allergic to medicines you give. The hallucinations should pass after a few minutes.
Charles Bonnet syndrome
It'sestimated that around 60 per centof people withvisual impairment may experience temporary visual hallucinations.
This is known asCharles Bonnet syndrome. It tends to affect older people who have started to lose their sight, although it can affect people of any age.
The hallucinations usually last for about 12 to 18 months. They can take the form of simple, repeatedpatterns or complex images of people, objects or landscapes.
Some of the most common causes of visual impairment include:
- age-related macular degeneration (AMD)– where the central part of the back of the eye (the macula, which plays an important role in central vision) stops working properly
- cataracts– when changes in the lens of the eye cause it to become less transparent (clear)
- glaucoma– where fluid builds up inside the eye, damaging the optic nerve (which relays information from the eye to the brain)
- diabetic retinopathy– where blood vessels that supply the eye become damaged from a build-up of glucose
Hallucinations in older people with delirium
Hallucinations can sometimes occur in frail older people who are ill. The hallucinations may start before other signs that the person is unwell.They may becaused by achest infectionorurine infection, for example.
Call the GP if an elderly relative, or person you know, suddenly develops hallucinations, particularly if they appear unwell in any other way.
More useful links
- How to use your health services
- Hearing Voices Network
- Mental Health Foundation
The information on this page has been adapted from original content from the NHS website.
For further information seeterms and conditions.
