Aetiological factors

Aetiological factors in schizophrenia include:

• hereditary factors:
  • it is generally accepted that there is a genetic component schizophrenia but size of the effect is unclear
  • studies of monozygotic twins have shown concordance rates in the development of schizophrenia varying between 30% and 60%
  • the concordance rate in dizygotic twins is 10-15%
    
    
• pre-morbid "schizoid" personality is associated with the development of schizophrenia:
  • schizoid traits include abnormal shyness, hypochondriasis, fanaticism and eccentricity
    
    
• childhood experiences
  
  
• biochemical factors - LSD and amphetamines can both produce schizophrenic-like psychoses
  
  
• physical factors - illnesses, operations, accidents or periods of reduced sleep can precipitate an acute schizophrenic psychosis or cause remission in an established schizophrenic
  
  
• life events such as bereavement or loss of a job, may precipitate onset or remission of schizophrenia
  
  
• cerebral tissue damage - head injury, cerebral tumour, Huntington's chorea and Wilson's disease occasionally produce schizophrenia-like disorders; temporal lobe epilepsy is associated with an increased incidence of schizophrenia; some schizophrenics have large ventricles