Explanations into Schizophrenia PSYA4

Genetic Factors

• Schizophrenia more common amonng biological relatives of person with schizophrenia.
• Twin Studies- Joseph pooled data shows concordance rate for MZ twins of 40% and DZ twins 7%.
• Use of blind diagnosis procedures lower concordance rate for MZ twins, but still much higher than DZ.
• Adoption study by Tienari- if biological mother schizophrenic 6.7% of adoptees also schizophrenic (2% of controls).

Dopamine Hypothesis

• Neurons that transmit dopamine fire too easily or too often, leading to symptoms of schizophrenia.
• Schizophrenics- abnormally high levels of D2 receptors.
• Evidence from large doses of amphetamines (dopamine agonist) causes hallucinations and delusions.
• Antipsychotic drugs- block dopamine and eliminate symptoms
• Parkinsons disease- treatment with L-dopa raises dopamine levels and can therefore also trigger schizo symptoms

Genetic Factors

• Enviroments of MZ twins may be more similar that DZ twins.
• Differences in concordance rates may reflect enviromental similarity rather than role of genetic factors.
• The fact that schizophrenia runs in families may be due to factors that have nothing to do with herritability (e.g expressed emotion)
• Adopted children from schizophrenic backgrounds may be adopted by particular type of parent making conclusions difficult to draw.
• Many studies have to include 'schizophrenia spectrum disorders' to show genetic influences.

Dopamine Hypothesis

• Drugs can increase schizophrenia symptoms as neurons try to compensate. Haracz found elevated dopamine levels in post-mortems of schizos who had taken medication.
• Neuroimaging studies failed to provide convincing evidence for altered dopamine activity in schizos.

• Provides clear predictions for example the effects of the neurons on schizo patients.
• The tests can also be proven easier or falsified easier.
• Biological theories normally arent the whole story as there may be an impact from the enviroment which isnt taken into account.
• There are methodological problems with the adoption studies as they may have not found statistical evidence without broadening the definition of schizo to include non-psychotic schizo spectrim orders. For exampke Kety found no cases of full schizo were found among cases of first degree relatives of adopted children identified with a schizo spectrum.

Psychological Theories

• Psychodynamic view of schizophrenia - result of regression to pre-ego stage and attempts to re-establish ego control.
• Some schizophrenic symptoms reflect infatile state, other symptoms are an attempt to re-establish control.
• Further features of disorder appear as individuals attempt to understand their experiences.
• They may reject feedback from others and develop delusional beliefs.

Socio-Cultural Factors

• Prior to schizo episode, patients report twice as many stressfull life events.
• Double-blind theory- contradictory messages form parents prevent coherent construction of reality leads to schizo symptoms.
• Expressed emotion- family communication style involving criticism, hostility and emotional over-involvement.
• Leads to stress beyond impaired coping mechanisms and so schizo.
• Labelling theory- symptoms of schizo seen as deviant from rules ascribed to normal experience. Diagnostic label leads to self-fulfilling prophecy.

Psychological Theories

• Very little evidence to support psychodynamic view of schizophrenia.
• Behaviour of parents assumed to be a key influence in development of schizophrenia but may be a consequence rather than a cause.
• Cognitive explanation supported by neurophysiological evidence e.g excess dopamine levels in the prefrontal cortex and the working memory adaptations.

Socio-Cultural Factors

• Some evidence challenges link between life events and schizophrenia. Evidence for link is only correlational not causal.
• Importance of family relationships in development of schizo shown in adoption study.
• Double-blind theory supported by Berger- schizos recalled more double-blind statements from mothers.
• Expressed emotion- has led to effective therapy for relatives.
• Schelf- 13 out of 18 studies consistent with predictions of labelling theory.
• Link supported in both retrospective and prospective studies.
• Expressed emotion effects much less common in non-individualist cultures.

• Recognises the importance the brain can have on out behaviour and the way it makes us behave.
• Its not easy to be falisified or to be proven correct as there is no physical evidence to be gained from it.
• Culture- expressing emotion is more common in the west however non-western cultures are individualist and are less likely to blame someone else for their schizo.