Schizophrenia. Clinical Characteristics (Symptoms). Explanations – Biological vs Psychological. Nature vs Nurture. Diathesis Stress Model. No-one believes Schizophrenia is completely caused by either genes or the environment. There must be an INTERACTION between the two.
Nature vs Nurture
Source: Gottesman (1991)
Why did Kety et al (1988) study adopted people with schizophrenia?
14% biological relatives developed schizophrenia
2.7% adopted relatives developed schizophrenia
QUESTION: what does this suggest?
How can this lead to new drug developments?Molecular Biology(AO1)
This theory claims that excessive amounts of dopamine or an oversensitivity of the brain to dopamine is the cause of schizophrenia
There are 3 pieces of evidence to support this:
1. Drugs which block dopamine (Phenothaiazines) reduce the symptoms of schizophrenia.
People with schizophrenia have abnormally large ventricles in the brain. Ventricles are fluid filled cavities. This means that the brains of schizophrenics are lighter than normal.
1. There is conflicting biological evidence
2. We cannot be sure that schizophrenia is one disorder
3. We cannot prove cause and effect
4. There are alternative explanations
5. It is difficult to separate out genes from social situations.
6. Genetic inheritance it is only a predictor of a ‘predisposition’ and is not a predictor of actually getting the disorder.
7. Biological explanations are therefore incomplete