Biological Explanation for Schizophrenia
- Created by: GracieFM
- Created on: 20-03-14 08:36
View mindmap
- Biological Explanation for Schizophrenia
- Dopamine Hypothesis Explanation
- Abnormally high levels of dopamine receptors at the synapse
- Increased dopamine in the mesolimbic pathway contributes to positive symptoms
- Increased dopamine in the mesocortical pathway contributes to negative symptoms
- Neurons that use the transmitter 'dopamine' fire too often and transmit too many messages or too often
- Certain D2 receptors are known to play a key role in guiding attention.
- Lowering dopamine activity helps remove the symptoms of schizophrenia
- Dopamine Hypothesis Evaluation
- Role of Drugs
- Strength because shows dopamine produces symptoms
- Amphetamines (agonists) lead to increase in DA levels
- Large quantities lead to delusions and hallucinaions
- If drugs are given to schizophrenic patient their symptoms get worse
- Parkinson's Disease
- Strength because shows dopamine produces symptoms
- Parkinson's sufferers have low levels of dopamine
- L-Dopa raises DA activity
- People with Parkinson's develop schizophrenic symptoms if they take too many L-Dopa
- Chlorphromazine (given to schizophrenics) reduce their symptoms by bloacking DZ receptors
- Post Mortem
- Strength because increased dopamine receptors in schizophrenicsa
- Autopsies have found that people with schizophrenia have a larger than usual number of dopamine receptors
- Increase of DA in brain structures and receptor density (left amygdala and caudat ncleus putamen)
- Concluded that DA production is abnormal for schizophrenia
- PET Scans
- Weakness because shows drugs don't reduce symptoms
- PET scans have suggested that drugs didn't reduce symptoms of patients diagnosed with disorder for 10 years or more
- Farde et al (1990)
- No difference in the number of dopamine receptors between schizophrenics and controls
- Negative Symptoms
- Weakness because drugs don't help these syptoms
- Not good at explaining negative symptoms
- Suggested that type 2 is related to a different king of abnormality such as brain structure
- Role of Drugs
- Genetic Factors
- Family Studies
- Gottesman (1991)
- Schizophrenia is more common in biological relatives, the more closely related, the higher the risk.
- The concorndance rate among identical MZ twins is 48% and DZ fraternal twins is 17%
- Gottesman (1991)
- Adoptive Studies
- Kety et al (1988)
- Found 14% of biological relatives of adopbtees were classified at schizophrenic
- Only 2.7% of adoptive relatives were found to be schizohprenic
- Kety et al (1988)
- Family Studies
- Dopamine Hypothesis Explanation
Comments
No comments have yet been made