Psychosis is a mental health problem that causes people to perceive or interpret things differently from those around them. It stops the person from thinking clearly, being able to tell the difference between reality and their imagination, and from acting in a normal way.

People may experience hallucinations – when they see things that other people don't. They may experience tastes, smells or physical sensations (like skin crawling) that have no obvious explanation. They may also hear voices that others don't. Sometimes the voices may be reassuring or helpful but often they can be critical and mean.

People may experience delusions – when they have beliefs that others do not share. These beliefs could be about the person themselves, (for example, about their status or importance) or the beliefs might also be about the world around them(for example, they are under threat).

Experiencing the symptoms of psychosis is often referred to as having a psychotic episode. The combination of hallucinations and delusional thinking can often severely disrupt perception, thinking, emotion and behaviour. Experiencing a psychotic episode can be very frightening for the person and those around them.

Psychosis isn't a condition in itself – it's a symptom of some of the more severe forms of mental health problems, such as bipolar disorder, schizophrenia or some forms of personality disorder. Psychosis can also be triggered by traumatic experiences, stress or physical conditions such as Parkinson's disease, a brain tumour, or as a result of drug misuse or alcohol misuse.