Hallucinations happen when someone sees, hears, smells, tastes or feels things that do not exist outside their mind. They are common in people with schizophrenia, and may be experienced as hearing voices.
Hallucinations can be frightening as they may be unexpected or unwanted, but there may be an identifiable cause. They can occur as a result of:
If you have hallucinations and are worried about them see your GP straight away.
Hallucinations can be very frightening and it’s important to be with someone you can trust who can support you.
In the meantime, the below information explains the typical types of hallucinations, including why they may happen and what you can do.

Hallucinations can also occur as a result of extreme tiredness or a recent trauma.

Hearing voices

Hearing voices is the most common type of hallucination in people with conditions such as schizophrenia. The voices can be critical, complimentary or neutral, and may engage the person in conversation. Hearning voices is a well recognised symptom of schizophrenia, dementia or bipolar disorder, but can be unrelated to mental illness.The experience is usually very distressing but it is not always negative. Some people who hear voices are able to live with them and get used to them or may integrate them as part of their life for example in the work they do.
It is not uncommon for recently bereaved people to hear voices and this may sometimes be the voice of their loved one.

Practical advice

Concerns about hallucinations should be discussed with your GP who may refer you to a psychiatrist if necessary. This is important as essential in understanding whether you have a serious mental illness and what course of treatment is appropriate.
Psychiatrists are a regular part of mental health teams in the community and specialise in hullinations and it is 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.
Please see the below support:
  • Talk to other voice hearers. Try the Hearing Voices Network.
  • Be open to discussing your voices.
  • Try to understand where the voices come from why, and what triggers them.

For more information and practical advice on dealing with voices in your mind, read the Mental Health Foundation’s fact sheet on hearing voices.

Drug-induced hallucinations

Illegal drugs and alcohol

People can experience hallucinations when they are high on illicit drugs such as amphetamines, cocaine, LSD or ecstasy. Hallucinations can also happen during withdrawal from alcohol or drugs if you suddenly stop taking them.
Drug induced hallucinations are usually visual but may affect other senses. Hallucinations include flashes of light or abstract shapes, or may even take the form of an animal or person. More often visual distortions occur that alter the person’s perception of the world around them.
These hallucinations can happen on their own or they can occur as a part of drug-induced psychosis. After long term use they may cause schizophrenia. It may be helpful to read an account of a drug-induced psychotic breakdown.
Some people take cannabis to “calm themselves” and relieve their psychotic symptoms without realising that in the longer term, the cannabis may make the psychosis worse.

Heavy use of alcohol may also lead to psychotic states, hallucinations and dementia.

Find out how to get help for a drug problem.


Various prescription medicines may cause hallucinations and elderly people may be at particular risk.
Hallucinations caused by medications can be dose related and usually go away when you stop taking the medicine. However never stop taking 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 and the side effects you may be experiencing,  so you can discuss the possibility of alternative medication or doses.

Hallucinations and sleep

It is relatively common for people to have hallucinations just as they are falling asleep (hypnagogic) or as they start to wake from sleep (hypnopompic).
Hypnagogic and hypnopompic hallucinations are especially common in people with the sleep disorder narcolepsy, although they are also common in people without this or any disorder. They are may be 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. If your child is unwell with a body temperature of over 37.5C (99.5F) and you think they are hallucinating, call your GP.
Encourage them to drink plenty of fluids and give them Paracetamol if required. The hallucinations should pass after a few minutes.
For more information, read about fever in children.

Charles Bonnet syndrome

It is estimated that around 60% of people with severe visual impairment may experience temporary visual hallucinations.
This is known as Charles Bonnet syndrome and tends to affect older people who have lost their sight, but can affect people of any age.
The hallucinations usually last for around 12-18 months and can take the form of simple patterns or detailed images.
Around 100,000 people in the UK are thought to be affected by Charles Bonnet syndrome.