Psychosis: Definition

Psychosis refers to a state in which perceptions or beliefs become substantially disconnected from shared reality. Common features include hallucinations, delusions and markedly disorganised thinking. A person might hear a voice without an external speaker or become convinced that ordinary events contain messages directed specifically at them. Experiences can feel entirely convincing, although awareness varies.

Psychosis is a description of particular experiences and difficulties with reality testing. It can occur in several psychiatric, substance-related and medical conditions. The meaning of an experience depends on its context, associated symptoms and development over time, including the person’s cultural background.

Psychosis is a symptom pattern, not a single disease. It can occur with schizophrenia, bipolar disorder, severe depression, substance effects and some neurological or medical illnesses. Unusual experiences alone are not enough to establish a psychotic disorder. Clinicians consider persistence, distress, functioning, cultural meaning and alternative explanations. Someone experiencing psychosis may still communicate clearly, work or recognise that something feels different. The term should therefore be used precisely rather than as a general label for confusion, anger or unpredictable behaviour. Understanding the cause and immediate needs guides the choice of care.

Reality testing refers to evaluating whether an interpretation fits available evidence and can be shared or checked with others. It can be impaired for one experience while remaining intact in other areas. This explains why a person can have a delusional belief and still reason accurately about many ordinary decisions, relationships or practical tasks.

Further reading: National Institute of Mental Health.