Biological explanation to schizophrenia

Question 1

what are the main components for the genetic basis of schizophrenia

Answer 1

• family studies
• candidate genes
• the role of mutation

Question 2

how do family studies prove the genetic basis for schizophrenia

Answer 2

• confirmed risk of scz increases in line with gentic similarity to a relative with the disorder.
• Gottesman’s 1991 large scale family study found that if an aunt had scz there is a 2% risk if developing it, 9% if theyre a sibling and 48% is theyre an identical twin.

Question 3

how do candidate genes prove genetic basis for schizophrenia

Answer 3

• schizophrenia is polygenetic as a number of genes are involved, most likely would be those coding for neurotransmitters like dopamine.
• Ripke et al 2014 combined data from genome wide studies of scz. Genetic makeup of 37,000 ppl with scz was compared with 113,000 controls. Found that scz is aetiologically heterogenous so there are different combinations of factors that can lead to the condition

Question 4

how does the role of mutation prove the genetic basis for scz

Answer 4

• mutation of prenatal DNA which can be caused by radiation/poison/viral infection.
• theres a positive correlation with parental age and risk of scz (Brown et al. 2002)

Question 5

evaluate the genetic basis for scz; strengths

Answer 5

• research support. Gottesman study and adoption studies like Tienari et al 2004 show biological risks are still there even if children have been adopted.
  -m Hikler et al. 2018 showed concordance rates of 33% for identical twins and 7% for non-identical twins. Shows some ppl are more vulnerable

Question 6

what are the weaknesses for genetic basis of scz

Answer 6

• Environmental factors also increase risk of getting scz.
• Morgan et al. 2017 found biological risk factors like smoking and THC rich cannabis in teen years (De Forti et al. 2015)
• childhood trauma could also make people more vulnerable. Studies show that 67% of ppl with scz reported at least one childhood trauma opposed to a control group of 38% with non-psychic mental health issues.

Question 7

what are the two parts to the biological approach

Answer 7

• genetic
• neural

Question 7

what are the two parts of the neural part of the biological explanation

Answer 7

• the original dopamine hypothesis
• the updates versions of the dopamine hypothesis

Question 8

what is the original dopamine hypothesis

Answer 8

• based on the discovery that drugs used to treat scz caused symptoms sililar to those with Parkinson’s disease- associated with low DA levels.
• therefore schizophrenia may be the result of high DA levels.
• The broca’s area is responsible for speech production so may also cause speech poverty or hallucinations

Question 9

what is the updated version of the dopamine hypothesis

Answer 9

• Davis et al. (1991) proposed addition of abnormally low DA in brain’s cortex.
• Low DA in prefrontal cortex (responsible for decision making) could explain cognitive problems such as negative symptoms. [Abnormal DA function.

Question 10

what is a strength to neural explanations

Answer 10

• There is evidence for dopamine thats involved in schizophrenia.
• Research has found that antipsychotic drugs reduce DA activity and intensity of symptoms (Tauscher et al. 2014)
• Some candidate genes act on the production of DA or DA receptors.
• Strongly suggests dopamine is involved in symptoms of schizophrenia.

Question 11

What is a weakness for neural explanations

Answer 11

• the central role of glutamate
• post mortem and live scanning studies have consistentley found raised levels of neurotransmitter glutamate in several brain regions of people with schizophrenia (McCutcheon et al. 2020)
• In addition, several candidate genes for scz are believed to be involved in glutamate production/processing.