- Regression of Sexual Drive: Freud offers a sexual explanation of this mental disease as of all the others. According to him, the main and fundamental causes of this disease is the regression of sexual energy and the ego towards the stage of the infant, self-love and sucking stage because the patient suffering from it is an adult and yet cannot adjust social responsibility with heterosexual love.
- Disorganization of Sex Glands: According to Kraepelin, the main cause of schizophrenia is that over-secretion of the sex glands lead to creation of stimulating chemicals in the digestive systems. Not much following is given to this viewpoint.
- Heredity: Studies of the heredity of such patients have led Kalimann, Stoddard and White among other psychologists, to the belief that its causes are heredity. But Rosanoff believes that along with heredity another important cause is the birth trauma. Presence of heredity does not seem very logical, as its sole cause.
- Environment: Pollack and Malzberg studied 175 patients of this disease and reached to the conclusion that environment plays a bigger part in creating this disease than does the heredity, and so psychologist today refutes the imPortance of environment in causing of schizophrenia.
- Biological causes: Adolf Meyer has mentioned biological maladjustment towards the environment as the main cause of schizophrenia to a repression of the life force and to repressed emotional complexes, which is caused by maladjustment with the environment.
- Instinct for self-respect: According to McDougall, when the patient is unable to find proper and desirable expression for his instincts of self-respect, . he becomes a prey to schizophrenia. Personality type: it is the opinion of some p'sychologist that only a certain personality type is susceptible to schizophrenic tendencies, primarily the introverted type of individual. But this concept of the personality type being more prone to schizophrenia has also not found much of the following among the thinkers of the mark.
- Conflicts between feminine and masculine elements: According to the neo Freudian Otto Rank, the primary cause of Schizophrenia is the conflict between feminine and masculine elements.
Lastly the apparent primary cause is the individual's disability to adjust with his environment.