(Science: psychiatry) A mental disorder or heterogeneous group of disorders (the schizophrenias or schizophrenic disorders) comprising most major psychotic disorders and characterised by disturbances in form and content of thought (loosening of associations, delusions and hallucinations) mood (blunted, flattened or inappropriate affect), sense of self and relationship to the external world (loss of ego boundaries, dereistic thinking and autistic withdrawal) and behaviour (bizarre, apparently purposeless and stereotyped activity or inactivity).
The definition and clinical application of the concept of the concept of schizophrenia have varied greatly. The DSM III R criteria emphasise marked disorder of thought (delusions, hallucinations or other thought disorder accompanied by disordered affect or behaviour), deterioration from a previous level of functioning and chronicity (duration of more than 6 months), thus excluding from this classification conditions referred to by others as acute, borderline, simple or latent schizophrenia. Originally called dementia praecox and characterised as a psychosis with adolescent onset and a chronic course ending in deterioration. The term schizophrenia was introduced by Bleuler because neither early onset nor terminal deterioration is an [[essenti 441 al]] feature, he emphasised the splitting and lack of personality integration seen in the disorder.
Origin: Gr. Phren = mind