Not to get too symantical but as Newtus said major mental illnesses are chronic as in permanent. Symptoms can be treated to reduce their severity but the illness remains incurable. Many acute symptoms are transitory like mania, depression and psychosis. At least my acute mania and acute depression while severe and awful subsided thankfully with treatment. I have worked with some schizophrenics who unfortunately are resistent to treatment, remain in a psychotic state and are typically in a residential setting.