Hallucinations explained: all five senses

Hallucinations can feel very real and frightening. A hallucination isn’t imagined in the everyday sense: the person truly hears, sees or feels it.

A hallucination is about the senses. A delusion is a belief others don’t share. The two can go together: a person who hears voices about them may come to believe the neighbours are plotting.

Causes the NHS lists

• Changes in eyesight, such as Charles Bonnet syndrome
• Dementia and Parkinson’s
• Drugs and alcohol
• Infection, or sudden confusion (delirium)
• Mental health conditions, including schizophrenia, bipolar disorder, severe depression and PTSD
• Migraine, a high temperature, severe hunger or lack of sleep
• Surgery and anaesthesia

Voices often seem to come from outside, such as behind you or far away. They may talk to the person, about them, or both. Some are comforting, some neutral, and some frightening.

The Hearing Voices Network estimates that 3 to 10% of people hear voices or have similar experiences. When one-off experiences like hearing your name called are included, it rises to around 75%.

After significant sight loss, some people see patterns, people or objects. This is called Charles Bonnet syndrome. It isn’t caused by a mental health problem, and most people know the images aren’t real.

In studies of healthy people kept awake, vision was the sense most often affected, in 90% of studies.

Causes include

• Ageing
• Growths in the nose
• Head injury
• Sinus infections
• Smoking

A different problem, parosmia, is when familiar smells seem distorted, so pleasant things smell unpleasant.

Temporal lobe seizures are often linked with a warning, or aura, of an unusual smell or taste, nausea, or feelings like déjà vu or fear.

Parkinson’s can cause smell changes, and less commonly smell hallucinations. Smell hallucinations can also be part of psychosis.

Causes include

• Contact with certain chemicals
• Head injury
• Poor oral hygiene and dental problems
• Some ear, nose and throat surgeries
• Upper respiratory and middle ear infections

In some focal seizures, a person stays aware but may taste, smell, see, hear or feel things that are not real.

In psychosis, hallucinations can involve taste as well as the other senses. Some people also fear their food or water has been tampered with. Responding to the fear calmly, without arguing, helps.

In studies of people kept awake for long periods, body sensations changed in 52% of studies, after vision.

Some drugs make people feel detached from their body or as if they are floating.

Severe alcohol withdrawal can bring hallucinations, confusion, fever and seizures. It is an emergency: call 911.

Feeling a loved one’s touch is one of the less common ways people sense someone who has died. Most such experiences are felt as comforting.

Touch hallucinations can happen in psychosis, Lewy body dementia and Parkinson’s, though they are less common than seeing or hearing things.

Examples

• Hearing your name called once
• Seeing or hearing things as you fall asleep or wake up
• Sensing a loved one after a death, especially if it feels comforting
• Short-lived experiences with a fever, migraine or severe hunger

See a provider soon if hallucinations

• Are getting in the way of sleep, work, school or relationships
• Are new, especially in an older adult
• Are upsetting or frightening
• Come with sight or hearing changes
• Come with unusual beliefs, or pulling away from people

If someone

• Has suddenly become confused, or isn’t making sense
• Has hallucinations that are quickly getting worse
• Hears voices telling them to harm themselves or others
• Is very agitated or aggressive
• Wants to harm themselves or someone else

If a child tells you they hear or see things, thank them for telling you. Ask what it’s like and how it makes them feel. A calm response makes it easier for them to keep talking.

Talk with their clinical provider if experiences are upsetting, happening often, or come with changes in sleep, school or friendships. A high temperature can also bring brief hallucinations, so get medical advice if a child is unwell.

Hearing Voices groups offer respectful, empowering spaces to talk about voices, visions and other unusual sensory experiences.

What helps

• Ask how it makes them feel
• Avoid arguing about whether it’s real
• Say something like “I don’t hear it, but I can tell it’s upsetting”
• Stay calm and use short, simple sentences

Sight-loss charities, dementia and Parkinson’s groups, grief groups and faith communities can all help people feel less alone. A kind, unhurried listener can make it easier to seek help.