PSYCHOSIS

plural Psychoses, any of several major mental illnesses that can cause delusions, hallucinations, serious defects in judgment and insight, defects in the thinking process, and the inability to objectively evaluate reality. It is difficult to clearly demarcate psychoses from the class of less severe mental disorders known as psychoneuroses (commonly called neuroses) because a neurosis may be so severe, disabling, or disorganizing in its effects that it actually constitutes a psychosis. But, in general, patients suffering from the recognized psychotic illnesses exhibit a disturbed sense of reality and a disorganization of personality that sets them apart from neurotics. Such patients also frequently believe that nothing is wrong with them, despite the palpable evidence to the contrary as evinced by their confused or bizarre behaviour. Psychotics may require hospitalization because they cannot take care of themselves or because they may constitute a danger to themselves or to others. Psychoses may be divided into two categoriesorganic and functional. Organic psychoses are those caused by a known physical abnormality, which in most cases is some organic disease of the brain. All other psychoses are called functional ones.