Biological Explanations

Question 1

Explain the genetic basis for schizophrenia, referring to Gottesman (1991)’s study.

Answer 1

In his family study he found a 48% chance of schizo amongst DZ twins. They share 100% of genes. This means that the disorder is hereditary.

However, this also means that 52% has to do with other causes, e.g. environmental.

Question 2

Explain the genetic basis for schizophrenia, referring to Ripke et al (2014)’s study.

Answer 2

Candidate genes are responsible for causing schizophrenia. Because a number of genes are involved, the disorder is called “polygenic”. In their study they found over a 100 genetic variations that may influence schizophrenia.

Because there are different genes, schizophrenia is described as AETIOLOGICALLY (cause of disease) HETEROGENOUS (multiple).

Question 3

Explain the genetic basis for schizophrenia, referring to Brown et al (2002)’s study.

Answer 3

Schiz can also be caused by genetic mutations. The risk of schizophrenia increases as the father’s age increases, due to mutations within the sperm.

Question 4

Explain the neural basis for schizophrenia, referring to neural correlates.

Answer 4

Neural correlates are structures or functions of the brain associated with schizophrenia.

E.g. the VENTRAL STRIATUM is associated with reward anticipation and reinforcement. Patients have been found to have less activity in this area, causing the negative symptom of avolition.

More commonly, the neurotransmitter DOPAMINE is associated with schizo, it plays a lot of key roles with brain functions.

Question 5

Describe the dopamine hypothesis.

Answer 5

It was found that antipsychotics (which reduce dopamine) caused the same symptoms as people with Parkinson’s (which involves low dopamine). This means that schizophrenia was caused by HIGH levels of dopamine = HYPERDOPAMINERGIA.

Too many dopamine receptors in the subcortex (inner of brain) caused over-activity of dopamine and therefore hallucinations (linked to positive symptoms).

Question 6

Describe the updated dopamine hypothesis.

Answer 6

This argues that LOW dopamine levels in the CORTEX (outer area) can also induce schizophrenia symptoms, particularly negative symptoms.

e.g. low dopamine in the prefrontal cortex which is responsible for cognition

Question 7

Evaluate the genetic basis for schizophrenia

Answer 7

• There is strong evidence using twin studies and adoption studies.
• Cannot be solely genetic, though, because concordance rate is not 100%.
• Environmental factors, therefore, also influence, e.g. trauma.

Question 8

Evaluate the dopamine hypothesis, referring to Curran et al (2004) and Tauscher et al (2014), as well as glutamate, and Smith et al (1977) + apomorphine.

Answer 8

• Curran: increasing dopamine through drugs worsened schizophrenic symptoms and induced it in people.
• Tauscher: Anti-psychotics reduce dopamine and intensity of symptoms.
• Other neurotransmitters like glutamate may be involved based on post-mortem studies showing raised levels.
• Hypothesis doesn’t explain what caused the high or low levels of dopamine.
• Smith: According to hypothesis, apomorphine should induce or worsen schizo symptoms since it increases dopamine, but it did not.