In early use: insanity, madness Later: specifically mental illness with prominent paranoid or other delusional symptoms; paranoid schizophrenia.
late paraphrenianoun a psychotic state with paranoid delusions and hallucinations occurring in the elderly..
Origin
Mid 19th century; earliest use found in British and Foreign Medico-chirurgical Review. From para- + ancient Greek ϕρήνphren + -ia, after French paraphrénie.