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Describe and Evaluate Biological Explanations for Schizophrenia. Diathesis-Stress Model. A theory that explains behaviour as both a result of biological and genetic Factors ("nature"), and life experiences ("nurture").
A theory that explains behaviour as both a result of biological and genetic
Factors ("nature"), and life experiences ("nurture").
This model thus assumes that a disposition towards a certain disorder may
result from a combination of one's genetics and early learning.
The term "diathesis" is used to refer to a genetic predisposition toward an
abnormal or diseased condition.
According to the model, this predisposition, in combination with certain kinds
of environmental stress, results in abnormal behaviour.
This theory is often used to describe the pronunciation of mental disorders,
like schizophrenia that are produced by the interaction of a vulnerable
hereditary predisposition, with precipitating events in the environment.
As each persons DNA is different from anyone else’s, this is their specific Genotype.
Some genes always lead to certain characteristics; these are known as dominant genes. To produce a characteristic, dominant genes need to be on only one pair of chromosomes (one copy).
Dizygotic twins (non-identical twins) share similar characteristics, much like a siblings.
Researchers have looked for a particular ‘Schizophrenia Gene’ without success.
It is now thought that combinations of certain genes might make people more vulnerable to Schizophrenia, but this does not necessarily mean that they will develop the symptoms.
The evidence shows that people who have a parent with Schizophrenia are more likely to develop it themselves.
Biochemical research has been centred on Dopamine, which is one of the chemicals that carry messages between brain cells.
The theory is that an excess of dopamine, or dopamine receptors may be involved in the development of Schizophrenia.
Complete the Gottesmann and Sheildsresearch worksheet.
How does this explain theDopamine Hypothesis
The Dopamine hypothesis states that the brain of schizophrenic patients produces more dopamine than normal brains.
(specifically the D2 receptor)
Normal Level of Dopamine In The Human Brain
Falkai et al 1988
Lindstroem et al (1999)
Chickens hatch from eggs, but a mother chicken must keep an egg warm in order for it to hatch
The Chicken or the Egg?
Schizophrenia or Faulty Chemicals?
Faulty chemicals cause schizophrenia but schizophrenia may cause faulty chemicals
Drugs may influence other systems that impact on schizophrenia so cant be 100% sure about their effects