Biological Explanations for Schizophrenia Flashcards
How many candidate genes are thought to contribute to the development of schizophrenia?
108
Name the term used when several candidate genes contribute to the development of a disease.
Polygenic
Explain how a mutated dopamine gene can lead to schizophrenia.
Mutated gene may cause increased dopamine production which has shown to lead to increased positive symptoms
Describe the correlation between paternal age and risk of developing schizophrenia.
Risk of developing schizophrenia increases with paternal age.
Explain why increased paternal age leads to increased risk of schizophrenia.
With increasing paternal age, sperm mutation in candidate genes for schizophrenia is more likely.
Give the percentage for the risk of developing schizophrenia when the father is under 25 years old.
0.7%
Give the percentage for risk of developing schizophrenia when the father is over 50 years old.
2%
What is the dopamine hypothesis?
A theory that suggests that increased dopamine leads to increased firing of neurones, causing more positive symptoms.
Excess numbers of dopamine receptors in Broca’s area causes what 2 symptoms of schizophrenia?
Hallucinations and delusions
Cognitive symptoms of schizophrenia are thought to be caused by low levels of dopamine in which area of the brain?
Pre frontal cortex
Do high or low levels of glutamate cause schizophrenia?
High levels
Explain the strength that there is research support for the genetic explanation for schizophrenia
Use the example of Gottesmans family studies.
Use the example of findings from Tienari’s adoption studies and how biological children raised by adoptive parents are still at risk of schizophrenia.
Give the concordance rates for risk of schizophrenia in MZ and DZ twins as discovered by Hilker.
Family studies such as Gottesman show that risk increases with genetic similarity to a family member with schizophrenia. Adoption studies such as Tienari’s show that biological children of schizophrenic parents are at heightened risk, even if they grow up in an adoptive family. A twin study by Hilker found a concordance rate of 33% for MZ twins and 7% for DZ twins.
This shows how increased genetic similarity can increase risk.
Explain the strength of there being support for the dopamine hypothesis.
Describe the treatments done for schizophrenia that have been proven to be effective.
Crossleys meta analysis found that medication leads to a reduction in which type of symptoms?
What is the treatment aetiology fallacy and what does this suggest about the cause of schizophrenia?
What does this mean we can’t be sure about for the cause of schizophrenia?
Treatments of schizophrenia that involve blocking of dopamine receptors have proven to be highly effective. For example, Crossley conducted a metanalysis and found that medication leads to a significant reduction in positive symptoms. As the drugs work, this shows that dopamine does contribute to development of schizophrenia. However, the success of treatments doesn’t necessarily mean that dopamine caused the condition in the first place. This is called the treatment aetiology fallacy, where the absence of a drug doesn’t mean the condition was caused by this. This therefore means we cannot be fully sure that high dopamine is the cause of schizophrenia.
Explain the limitation of environmental factors increasing the risk of schizophrenia.
Give 2 examples of biological risk factors.
Give 2 examples of psychological risk factors.
Give the percentage that Morkved found for schizophrenia patients experiencing at least one childhood trauma. Give the percentage for the control group who had different mental disorders.
What does this suggest about the genetic explanation for schizophrenia?
This includes biological and psychological influences. Biological risk factors include birth complications and smoking cannabis in teenage years.
Psychological risk factor includes childhood trauma which leaves people more vulnerable to mental health problems in adulthood, with a particular link to schizophrenia. Morkved found that 67% of schizophrenia patients with related psychotic disorders reported at least one childhood trauma as opposed the 38% of a matched group with non-psychotic mental disorders.
This means that genetic factors alone cannot provide a complete explanation for schizophrenia.
Explain the limitation surrounding neural correlates.
Why is neural correlate research useful?
Explain the issues with correlations in the context of brain structure and cause of schizophrenia symptoms.
Research into neural correlates is useful for flagging up particular brain systems that may not work properly, however, there may be issues with correlations, as it is hard to tell whether unusual activity in a region of the brain is a cause of the symptom. For example, we don’t know whether schizophrenia leads to high dopamine or whether high dopamine leads to schizophrenia. Therefore, the existence of neural correlates tells us little about schizophrenia itself.
