[S] Biological explanations Flashcards
What have family studies found?
Schizophrenia is more common amongst biological relatives of the sufferer, and the closer the genetic link is, the greater the risk of schizophrenia.
What are the concordance rates for children with one schizophrenic parent and two schizophrenic parents?
One schizophrenic parent - 13%
Two schizophrenic parents - 46%
What did Joseph (2004) find the concordance rate for twins was?
Identical - 40.4%
Non-identical - 7.4%
What did Tienari et al (2000) find out about adoptees with biological schizophrenic mothers?
Out of 164 children, 11 were diagnosed with schizophrenia compared with 4 from a control group whose mothers were not schizophrenic.
What does the dopamine hypothesis suggest?
Messages from neurons that transmit dopamine fire too easily or too often, leading to the characteristic symptoms of schizophrenia.
What are schizophrenics thought to have?
Abnormally large numbers of D₂ receptors on receiving neurons.
What do dopamine neurons guide?
Attention, which could explain some schizophrenic symptoms.
What can cause hallucinations similar to those of a schizophrenic?
Large doses of amphetamines.
What do anti-psychotic drugs do?
Block dopamine activity.
Who are low levels of dopamine found in?
Sufferers of Parkinson’s disease, some who took dopamine agonising drugs had schizophrenic symptoms.
Which part of the brain structure could be responsible for schizophrenia?
Lateral ventricles, in schizophrenics they are enlarged.
What does research suggest about the prefrontal cortex activity of schizophrenics?
They have lower activity in this area of the brain.
What else has been suggested as a cause of schizophrenia?
Viral infections prenatally.
Evaluate genetic factors in schizophrenia in four points.
- Heredity could be due to common rearing factors and shared environments.
- Higher concordance rate of identical twins could be due to the fact they are likely to be brought up more similarly than non-identical twins.
- The fact that there is not a 100% concordance rate suggests schizophrenia is caused by more than just genetics.
- Not everyone with schizophrenia has a relative who also suffers.
Evaluate the dopamine hypothesis in four points.
- Using dopamine blockers can have the opposite effect and increase dopamine in order to compensate for the loss.
- There is no convincing evidence of altered dopamine activity in schizophrenics.
- It is difficult to establish cause and effect.
- Drugs such as clozapine which address serotonin levels as well have been more effective, suggesting the dopamine hypothesis is not a full explanation.
