Biological Explanations of Schizophrenia Flashcards
GENETIC FACTORS
Family studies
The closer the degree of genetic relatedness, the greater the risk. Children with two schizophrenic parents have a concordance rate of 46% whereas only is only 13%
GENETIC FACTORS
Family studies evaluation- other factors
Research has shown there is a genetic link as schizophrenia runs in families, however it may be more to do with common rearing patterns rather than genes. Expressed emotion could be a factor with the negative emotions in a family causing stress and hence a schizophrenic episode.
GENETIC FACTORS
Twin studies
Early research has found that the concordance rate for mz twins was 40% more recent research however, has found a low concordance rate. Despite this researchers conclude that there is still a genetic link because the link for MZ twins was higher than that of DZ twins.
GENETIC FACTORS
Twin studies evaluation-reared more similarly.
MZ twins are treated more similarly than DZ twins meaning that the higher concordance rate reflects nothing more than environmental differences rather than genetics
GENETIC FACTORS
Adoption studies
Out of 164 adoptees whose biological mothers had schizophrenia, 11 of them also were diagnosed with it with only 4 of the control group being diagnosed. Showing the strong genetic link.
GENETIC FACTORS
Adoption studies evaluation- known knowledge the children are schizophrenic
adoptive parents are informed of the background of the child prior to selection for adoption. hence they are likely to treat them differently-causing it?
The dopamine hypothesis
The key role of dopamine in schizophrenia is highlighted in 3 sources of evidence. what are these 3?
Amphetamines
Antipsychotic drugs
Parkinson’s disease
The dopamine hypothesis
what does the dopamine hypothesis state causes schizophrenia?
Messages from neurons that transmit dopamine fire too easily or too often leading to symptoms of schizophrenia. Schizophrenics have high levels of D2 receptors on neurons which result in more dopamine binding and hence firing.
The dopamine hypothesis
How do amphetamines support dopamine plays a role in schizophrenia?
It is a dopamine agonist which stimulates nerve cells containing dopamine causing the synapse to be flooded with dopamine. Large doses of dopamine cause hallucinations and delusions.
The dopamine hypothesis
How do antipsychotic drugs support the role of dopamine?
These drugs block the activity of dopamine in the brain eliminating the symptoms of hallucinations and delusions. Because they alleviate the symptoms, it strengthens the case for them being a factor in schizophrenia.
The dopamine hypothesis
How does Parkinson’s disease support the role of dopamine in schizophrenia?
Low levels of dopamine are found in those with Parkinson’s disease. Those who were taking a drug to raise their levels of dopamine were developing schizophrenic symptoms.
The dopamine hypothesis
What are the 4 evaluation points of the dopamine hypothesis?
Evidence from the success of drug treatments to alter dopamine levels
Post-mortem studies
PET scans
Evolutionary
The dopamine hypothesis
Evaluation
Evidence from drug treatments being a success
Antipsychotic drugs when tested with a placebo produced the lowest amount of relapse rates compared to over half with the placebo showing its effectiveness.
The dopamine hypothesis
Evaluation
post-mortem studies
Drugs used to stop dopamine can actually increase it as neurons struggle to compensate for the sudden deficiency. In post-mortem studies, most of those studies showed increased dopamine levels also showed those people have received antipsychotic drugs beforehand.
The dopamine hypothesis
Evaluation
PET scans
PET scans have allowed researchers to investigate dopamine activity more precisely. However, these studies have yet failed to provide any convincing evidence of altered dopamine levels.
