A growing body of knowledge indicates that genetics plays an important role in the development of schizophrenia.
Biochemical factors
One theory suggests that schizophrenia may be caused by an excess of dopamine activity in the brain.
Abnormalities in other neurotransmitters have also been suggested
Physiological factors
Viral infection
Anatomical abnormalities
Electrophysiology
Epilepsy
Huntington’s disease
Birth trauma
Head injury in adulthood
Alcohol abuse
Cerebral tumor
Cerebrovascular accident
Systemic lupus erythematosus
Psychological factors
These theories no longer hold credibility. Researchers now focus their studies of schizophrenia as a brain disorder.
Psychosocial theories probably developed early on out of a lack of information related to a biological connection.
Environmental Influence
Sociocultural factors: Poverty has been linked with the development of schizophrenia.
Downward drift hypothesis: Poor social conditions seen as consequence of, rather than a cause of, schizophrenia
Stressful life events may be associated with exacerbation of schizophrenic symptoms and increased rates of relapse.
Studies of genetic vulnerability for schizophrenia have linked certain genes to increased risk for psychosis and particularly for adolescents who use cannabinoids.
Theoretical integration
Schizophrenia is most likely a biologically based disease, the onset of which is influenced by factors in the internal or external environment.