Many investigators divide the schizophrenia into subgroups, which together are referred to as the "schizophrenias. The types of schizophrenia distinguished traditionally are: simple, catatonic, hebephrenic, and paranoid schizophrenia.
Simple schizophrenia is a type of schizophrenia in which the illness usually begins slowly, often in early adolescence. The patient gradually becomes apathetic, less intelligent in his behavior, and is inclined to withdraw from all interaction with his surroundings.
Catatonic schizophrenia has typical phases of stupor, excitement and negativism, and involves a gross deterioration of personal habits, which may degenerate into a near-vegetative form of living.
Hebephrenics show a marked bizarreness and absurdity in their reactions, and, as they deteriorate show increasing disorganization of most psychological functions.
One of the most common types of schizophrenia is paranoid schizophrenia. It typically entails systematic delusions of persecution, and ideas of reference in which the patient reads personal significance into the everyday actions and ordinary speech of others.
These types of schizophrenia are not mutually exclusive, but tend to overlap regarding some symptoms.