functional psychosis

…into two categories: organic and functional. Organic psychoses are characterized by abnormal brain function that is caused by a known physical abnormality, which in most cases is some organic disease of the brain. However, altered brain function that precipitates hallucinations and delusions is more often associated with specific psychiatric disorders,…

Functional psychoses were believed to have no physical brain disease evident upon clinical examination. Much research suggests that this distinction between organic and functional is probably inaccurate. Most psychoses are now believed to result from some structural or biochemical change in the brain.