Psychosis is a generic psychiatric term for mental states in which the components of rational thought and perception are severely impaired. Persons experiencing a psychosis may experience hallucinations, hold delusional beliefs (e.g.paranoid delusions), demonstrate personality changes and exhibit disorganized thinking. This is often accompanied by lack of insight into the unusual or bizarre nature of such behavior, difficulties with social interaction and impairments in carrying out the activities of daily living. A psychotic episode is often described as involving a "loss of contact with reality". Wikipedia Definition of Psychosis
More details of the research to be performed in this area may be found in the work programme for psychosis.