psychotic
adjective /saɪˈkɒtɪk/
  /saɪˈkɑːtɪk/
(medical)- suffering from severe mental illness, so that the person loses contact with reality 
- a psychotic patient
 
 - (of a mental illness) affecting the mind in a severe way that makes the person lose contact with reality
- a psychotic disorder/illness
 - He suffered a psychotic episode two years ago.
 
 see also psychosis