PSYCHE n. + -OSIS suffix, in sense 1 after German Psychose and NEUROSIS n. Compare scientific Latin psychosis (1846 or earlier in a medical context in a German source), French psychose (1859). Compare also ancient Greek fact or action of giving soul or life to, animation, principle of life.
- Medicine. and Psychology. Originally: any kind of disordered mental state or mental illness. Later: spec. severe mental illness, characterized by loss of contact with reality (in the form of delusions and hallucinations) and deterioration of intellectual and social functioning, occurring as a primary disorder or secondary to other diseases, drug ingestion, etc.; an instance of this.