Genetic basis of Schizophrenia

Question 1

What are the biological explanations of schizophrenia?

Answer 1

-genetic basis of schizophrenia
-dopamine hypothesis
-Neural Correlates

Question 2

What does the genetic basis of schizophrenia suggest?

Answer 2

-that biological characteristics are inherited from parents- a faulty version of a gene initially occurs due to random mutation, but this can then be inherited by the individual’s offspring.
-many candidate genes have been identified that contribute to the risk of developing schizophrenia.

Question 3

What is an example candidate gene underlying schizophrenia and what does it do?

Answer 3

COMT gene (located on chromosome 22) which controls an enzyme that breaks down dopamine.
-If a person inherits a low activity variant of the COMT gene, the enzyme is less effective, so dopamine levels are allowed to increase.
-Excessive dopamine activity has been linked to hallucinations, which are a symptom experienced by schizophrenic patients

Question 4

What does a poly genetic explanation propose?

Answer 4

proposes that symptoms of schizophrenia are a result of a complex combination of many candidate genes (lowers predictive validity) and that no single gene is responsible.

Question 5

What is a way of investigating the genetic basis of schizophrenia?

Answer 5

twin studies- involve large samples of mz twins and dz twins when one of the twins has been diagnosed with schizophrenia.
-Concordance rates are then calculated separately for the MZ and DZ samples, which is the number of twins within each sample who both have the disorder, usually represented as a percentage.
-If the concordance rate is significantly higher for MZ twins than for DZ twins, this suggests schizophrenia has a genetic basis because MZ twins share 100% of their genetic material, whereas DZ twins share approximately 50%