Schizophrenia: Biological Explanations

Question 1

Name the two biological factors influencing schizophrenia

Answer 1

1) Genetic factors

2) The dopamine hypothesis

Question 2

Name the three types of studies within genetic theory

Answer 2

1) Family studies
2) Twin studies
3) Adoption studies

Question 3

Key reason for family studies in determining biological explanation?

Answer 3

Find individuals with SZ and determine whether their biological relatives are similarly affected more often than non-biological relatives.

Question 4

What have family studies established?

Answer 4

SZ is more common among biological relatives; closer degree of genetic relation shows greater risk.

Question 5

Family studies:

Concordance rate for children with two SZ parents compared to children with one SZ parent?

Answer 5

Two SZ parents: 46%

One SZ parent: 13%

Question 6

What opportunity do twin studies offer?

Answer 6

Opportunity for researchers to investigate relative contributions of genetic and environmental influences.

Question 7

Twin studies:

What would it mean if there were a higher concordance rate of SZ between monozygotic twins than dizygotic twins?

Answer 7

The greater concordance rate is due to genetic factors.

Question 8

Who studied concordance rate of twins?

Answer 8

Joseph (2004)

Question 9

What did Joseph (2003) find by pooling all twin study data prior to 2001 regarding concordance rates?

Answer 9

Concordance rate for monozygotic twins was 40.4%

Rate for dizygotic twins was 7.4%

Question 10

What do adoption studies allow researchers to do?

Answer 10

To study genetically related individuals who have been reared apart; allows them to distinguish between genetic and environmental factors.

Question 11

Who studied 164 adoptees with SZ mothers in Finland?

Answer 11

Tienari et al (2000)

Question 12

What did Tienari et al (2000) find in his study of 164 adoptees with SZ biological mothers?

Answer 12

Adoptees with SZ mothers had 6.7% rate of diagnosis whereas the control group with healthy mothers only had rate of 2% diagnosis.

Genetic liability confirmed.

Question 13

Evaluation: ☹️

Family studies: what has research shown that may be the main reason for schizophrenia to run in a family instead of genetics?

Answer 13

May be more to do with common rearing patterns or other factors that have nothing to do with heredity.

Question 14

Evaluation: ☹️

Family studies: research on expressed emotion has shown what?

Answer 14

The negative emotional climate in some families may lead to stress beyond an individual’s already impaired coping mechanisms, leading to a SZ episode.

Question 15

Evaluation: ☹️

Twin studies: what crucial assumption behind twin research may be wrong?

Answer 15

Assumption that the environments of monozygotic and dizygotic twins are equivalent.

Question 16

Evaluation: ☹️

Twin studies: who pointed out that MZ twins are treated more similarly and share more similar environments than DZ twins?

What does this mean?

Answer 16

Joseph (2004)

There is reason to believe that the difference in concordance rates reflect nothing more than the environmental differences that distinguish the two types of twin.

Question 17

Evaluation: ☹️

Adoption: what is the (false) general assumption of adoption studies?

Answer 17

Assumption that adoptees are not ‘selectively placed’ ie adoptive parents who adopt children with SZ mothers are no different than adoptive parents who adopt children with a normal background.

Question 18

Evaluation: ☹️

Adoption: who pointed out that adoptees are likely to be selectively chosen by people who know their background?

Answer 18

Joseph (2004)

Question 19

What is dopamine?

Answer 19

One of many neurotransmitters that operate the brain.

Question 20

What does the dopamine hypothesis suggest about the role of dopamine in SZ?

Answer 20

Messages from neuroma transmit dopamine too easily and too often- leading to SZ characteristics.

Question 21

What are the three main sources of evidence for the dopamine hypothesis?

Answer 21

1) amphetamines
2) antipsychotic drugs
3) Parkinson’s disease

Question 22

How has the use of amphetamines highlighted the role of dopamine in SZ?

Answer 22

Amphetamines are dopamine agonists, stimulating nerve cells containing dopamine causing the synapse to be flooded with it. Large doses of the drug can cause characteristics such as hallucinations and delusions.

Question 23

How has the role of antipsychotic drugs highlighted the role of dopamine in SZ?

Answer 23

These drugs are dopamine antagonists because they block dopamine activity; this leads to reduced or eliminated symptoms. This strengthens biological argument.

Question 24

How has Parkinson’s disease research highlighted role of dopamine in SZ?

Answer 24

Low levels of dopamine activity found in people who suffer Parkinson’s disease, a degenerative neurological disorder. It was found that some people taking the drug ‘L-Dopa’ to raise levels of dopamine were developing SZ-like symptoms.

Question 25

Evaluation: ☹️

What is a major problem for the dopamine hypothesis?

Answer 25

The drugs used to treat SZ by blocking dopamine activity can actually increase it as neurons struggle to compensate for the sudden deficiency.

Question 26

Evaluation: ☹️

Who conducted a review of post mortem studies of SZ patients?

Answer 26

Haracz (1982)

Question 27

Evaluation: ☹️

What did Haracz (1982) find when he conducted a review of post mortem studies?

Answer 27

Found that most studies consisted of patients who had been given antipsychotics soon before death, resulting in elevated dopamine levels. Post mortems of patients who had not received medication showed that these individuals had normal levels of dopamine.

Question 28

Evaluation: ☹️

What method of research has developed and what has this allowed researchers to do?

Answer 28

Neuroimaging techniques improved (ie PET scan) allowing researchers to investigate dopamine activity more precisely than studies that measured metabolites (waste product of dopamine).

Question 29

Evaluation: ☹️

Why has improved neuroimaging technique undermined dopamine hypothesis?

Answer 29

Although the technique has improved, neuroimaging studies have still failed to provide convincing evidence of altered dopamine activity in the brains of SZ patients.