English Reference
Noun

psychosis

n. C / U
C2 Proficiency US /saɪˈkoʊsəs/ UK /saɪkˈəʊsɪs/ psy·chosis Psychology

n.a serious mental condition where a person loses touch with reality. You might see or hear things that are not there or believe things that are not true.

n.a severe mental disorder in which thought and emotions are so impaired that contact is lost with external reality. Often involves hallucinations or delusions.


SIMPLE

The patient suffered from a brief period of psychosis.

CONTEXTUAL

Doctors worked to determine whether the patient's psychosis was caused by a medical condition or a reaction to new medication.

COMPLEX

Early intervention in cases of drug-induced psychosis is critical to prevent long-term cognitive decline and to help the individual reintegrate into their social and professional environment.

Usage

Uncountable when referring to the general state; countable when referring to a specific episode or instance.

Lindsay Clancy has admitted killing her daughter and two sons but has pleaded not guilty to murder, saying she was experiencing postpartum psychosis.

BBC News· 18 Aug 2026

While prosecutors have been arguing that Clancy acted intentionally and should be held criminally responsible, her defense has said she suffered from postpartum psychosis.

The Guardian· 15 Aug 2026

From psych- + -osis or from Ancient Greek ψύχωσις (psúkhōsis, “animation, principle of life”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Ancient Greek ψύχωσις
Level C2 · Proficiency
Frequency Frequent
Updated