The word psychosis is used to describe conditions which affect the mind, where there is some loss of contact with reality.
Psychosis varies greatly and the term covers a number of related illnesses.
When someone becomes ill in this way and loses contact with reality it is called a psychotic episode. People who have experienced this often call it spinning out or going off the planet. With time and the right treatment, most people make a full recovery from the experience. Many may never have another episode. A minority experience psychotic symptoms on a daily basis.