The symptoms of schizophrenia are sometimes subdivided into primary symptoms, which occur in every schizophrenic, and secondary symptoms, which occur only in some schizophrenics and in other kind of patients, too. The primary symptoms of schizophrenia are affective disturbance, such as dull or apathetic emotional reactions, withdrawal or loss of interest in the environment and other people, and thought disturbances. Secondary symptoms include autism or absorption in an inner phantasy world, delusions, hallucinations, and odd behavior such as posturing and grimacing.
Schizophrenic patients often report feelings of depersonalization and perceptual abnormality such as the flatness, remoteness or unreality of their external environment. Depending on the types of schizophrenia, there is good empirical evidence that some schizophrenics experience disturbances of body image. Feelings of depersonalization are not particularly common among schizophrenics, but are common in compulsive depressive patients and in normal individuals under stress. The classification of schizophrenia by symptoms has not been successful, because the symptons overlap and change over time in the life of a patient.
Arieti (1955) distinguished four successive stages in the course of schizophrenia. In the first stage the major symptom is anxiety; in the second, apathy and withdrawal from reality; in the third stage, regressive habits appear and symtoms become blurred; and in the fourth stage, crude primitive habits predominate. However, nowadays modern treatment ensures that few schizophrenic patients pass beyond the second stage.