Definition of Schizophrenia | Etiology of schizophrenia

Definition of Schizophrenia

Schizophrenia is a psychotic condition characterized by a disturbance in thinking, emotions, volitions and faculties in the presence of clear consciousness, which usually leads to social withdrawal. The word “Schizophrenia” was coined in 1908 by the Swiss psychiatrist Eugen Bleuler. It is derived from the Greek words skhizo (split) and phren (mind). In ICD10, schizophrenia is classified under the code F2.


Schizophrenia is the most common of all psychiatric disorders and is prevalent in all cultures and in all parts of the world. About 15 percent of new admissions in mental hospitals are schizophrenic patients. It has been estimated that patients diagnosed as having schizophrenia occupy 50 percent of all mental hospital beds. About three to four per 1000 in every community suffer from schizophrenia. About one percent of the general population stands the risk of developing this disease in their lifetime. Schizophrenia is equally prevalent in men and women. The peak ages of onset are 15 to 25 years for men and 25 to 35 years for women. About two-thirds of cases are in the age group of 15 to 30 years. The disease is more common in lower socio-economic groups.

Etiology of schizophrenia

The cause of schizophrenia is still uncertain. Some of the factors involved may be:

Genetic Factors

The disease is more common among people born of consanguineous marriages. Studies show that relatives of schizophrenics have a much higher probability of developing the disease than the general population. The prevalence rate among family members of schizophrenics is as follows:

· Children with one schizophrenic parent: 12%

· Children with both schizophrenic parents: 40%

· Siblings of schizophrenic patient: 8%

· Second-degree relatives: 5-6%

· Dizygotic twins of schizophrenic patients: 12%

· Monozygotic twins of schizophrenic patients: 47%

Biochemical Factors

Dopamine hypotheses: This theory suggests that an excess of dopamine dependent neuronal activity in the brain may cause  chizophrenia.

Other biochemical hypotheses: Various other biochemicals have been implicated in the predisposition to schizophrenia. These include abnormalities in the neurotransmitters nor epinephrine, serotonin, acetylcholine and gamma-aminobutyric acid (GABA), and neuroregulators such as prostaglandins and endorphins.

Psychological Factors

  • Family relationship act as major influence in the development of the illness:
  • Mother-child relationship: Early theorists characterized the mothers of
  • schizophrenics as cold, over-protective and domineering, thus retarding the ego development of the child.
  • Dysfunctional family system: Hostility between parents can lead to a schizophrenic daughter
  • Double-bind communication: Parents convey two or more conflicting and incompatible messages at the same time.

Social Factors

Studies have shown that schizophrenia is more prevalent in areas of high social mobility and disorganization, especially among members of very low social classes. Stressful life events also can precipitate the disease in predisposed individuals.


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