Hallucinations happen when your brain creates a sensory experience without a matching source around you. You might hear, see, smell, taste or feel something that other people do not, but the experience can feel completely real.  

Here we explain why hallucinations happen and where to find support. 

What are hallucinations? 

A hallucination is hearing, seeing, smelling, tasting or feeling something that does not have an external physical source. Calling something a hallucination does not mean the experience feels imaginary. To the person experiencing it, it can feel as vivid and real as any other sensation. 

Hallucinations can be unsettling or frightening. But there are many possible causes, and experiencing them does not automatically mean you have a particular mental illness. 

What are the different types of hallucination? 

Hallucinations can affect any of your senses: 

Auditory hallucinations: Hearing sounds or voices that other people cannot hear. 

Visual hallucinations: Seeing people, objects, lights or other images that are not physically there. 

Olfactory hallucinations: Smelling something without an external source. 

Gustatory hallucinations: Experiencing a taste without something causing it. 

Tactile hallucinations: Feeling sensations on or inside your body without a physical cause. 

Why do hallucinations happen? 

Your brain constantly receives information from your senses and works out what it means. Hallucinations are thought to involve changes in this processing, so your brain produces a sensory experience without a corresponding external source. 

There is no single cause. Hallucinations can be associated with psychosis and conditions such as schizophrenia, bipolar disorder and severe depression.

They can also have physical causes, including Parkinson's disease and dementia. Lack of sleep, some medicines and alcohol or drug use can play a part too. 

Because the causes are so varied, it is important not to make assumptions about what a hallucination means. 

What should I do if I'm experiencing hallucinations? 

If you are experiencing hallucinations, particularly for the first time or if they are affecting your day-to-day life, speak to a healthcare professional. Finding out what may be causing them can help you get the right support. 

Treatment depends on the cause and your circumstances. It may include talking therapies, medication, practical support or treatment for an underlying physical or mental health condition. 

Experiencing hallucinations can feel confusing or frightening, but support is available. Rethink Mental Illness aims to give people severely affected by mental illness and their loved ones clear, practical information and support. 

Find support for hallucinations and mental illness 

If hallucinations are affecting you or someone you care about, you do not have to work out what to do alone. Visit our hallucinations information page.