Biological explanations Flashcards
The biological explanation is split into three models? What are the names of the three models?
1) Roles of genetics
2) Dopamine hypothesis
3) Neural correlation
Outline the role of genetic explained by Gottesman and Shields (twin studies)
Gottesman and Shields reviewed five twin studies to report a concordance rate of between 75% and 91% for MZ twins with severe forms of schizophrenia
Also an increased risk of schizophrenia in adopted children with a biological parent with schizophrenia and an increased risk of schizophrenia in siblings with schizophrenia
This suggests that genetics plays a larger role with chronic forms of disorder
What did Gottesman and Shields conclude from their studies?
Gottesman and Shields concluded that as genetic similarity increases so does the probability of sharing schizophrenia. For example, twins, siblings have a higher chance of sharing schizophrenia than cousins
What are neural correlates?
Neural correlates are measurements of the structure or function of the brain that correlate with an experience, in this case schizophrenia
Outline the dopamine hypothesis, highlighting the neurochemical approach
The dopamine hypothesis explains the effect of high and low levels of dopamine in the subcortex and cortex.
The hyperdopaminergia in the subcortex refers to high levels of dopamine in the subcortex. For example, high levels of dopamine in Broca’s area may explain speech poverty.
The hypodopaminergia in the cortex refers to low levels of dopamine in the prefrontal cortex. This may account for negative symptoms of schizophrenia as prefrontal cortex is responsible
What do neural correlates state about negative symptoms?
The neural correlates states abnormality in the ventral striatum can explain avolition in schizophrenic patients. Showing there are lower levels of activities found in the ventral striatum in the brains of people with schizophrenia.
What do neural correlates state about positive symptoms?
The neural correlate states low levels of activity in the temporal and cingulate gyrus may explain auditory hallucinations
What do neural correlates state about enlarged ventricles in schizophrenic patients?
People with schizophrenia will have enlarged ventricles. These are associated with damage to central brain areas and prefrontal cortex. These damages have been associated with negative symptoms
What is a strength of the biological explanation of schizophrenia? (real life applicability/ecological validity)
There is strong supportive evidence for genetic vulnerability to schizophrenia. Research led by Pekka Tienari et al found that children of schizophrenic sufferers are still at heightened risk of schizophrenia if adopted into families with no history of schizophrenia. This shows that the genetic basis of schizophrenia has valid conclusions that have ecological validity
What is a limitation of the biological explanation of schizophrenia? (reductionism)
The dopamine hypothesis can be accused of being reductionist. It suggests that too high or too low levels of dopamine can cause schizophrenia. However, there may be many other neurotransmitters involved in the development of schizophrenia
What is a strength of the biological explanation of schizophrenia? (small sample size + population validity)
Weinberger carried out MRI scans on two 28 year old MZ twins. The brain scans showed that the twin who suffered from schizophrenia had enlarge ventricles compared to the twin who did not have the disorder. However it lacks population validity because the sample size is too small(being based on two people), so it cannot be generalised to the wider world
What is a limitation of the biological explanation of schizophrenia? (Juckel et al)
Research into the neural correlates of schizophrenia is correlational. Juckel et al found lower levels of activity in the ventral striatum in patients with schizophrenia. It follows that abnormality in the areas like the ventral striatum may be involved in the development of avolition. There are problems with correlational research
