Biological explanations

Question 1

What is the genetic explanation of schizophrenia?

Answer 1

Several genes increase an individual’s overall vulnerability to developing schizophrenia

Question 2

What has replaced the traditional correlational twin, family and adoption studies when studying genetics?

Answer 2

Gene mapping

Question 3

What did Gottesman and Shields find?

Answer 3

If one MZ twin develops schizophrenia there is a 28% chance that the other twin will also develop the disorder

Question 4

What did Sorri et al. find?

Answer 4

Performed a longitudinal study for 21 years on Finnish adoptees and found that adoptees with a high genetic risk of developing schizophrenia were more sensitive to non-healthy rearing patterns, suggesting that environmental factors (and their interaction with genetic factors) are important too

Question 5

What is currently the biggest indicator/risk factor for schizophrenia?

Answer 5

VCFS - the gene for cleft pallet

Question 6

What is the dopamine hypothesis?

Answer 6

One neural correlate explanation: Dopamine acts to increase the rate of firing of neurons during synapse, which enhances communication between neurons. However, if too much dopamine is released it can lead to the onset of schizophrenia

Question 7

What dopamine releasing drug creates schizophrenic symptoms in non-schizophrenic patients?

Answer 7

L-dopa

Question 8

What does Davis believe?

Answer 8

High levels of dopamine in the mesolimbic dopamine system are associated with positive schizophrenic symptoms while high levels in the mesocortical dopamine system are associated with negative symptoms

Question 9

High levels of dopamine in the __________ dopamine system are associated with positive schizophrenic symptoms

Answer 9

Mesolimbic

Question 10

High levels of dopamine in the __________ dopamine system are associated with negative symptoms

Answer 10

Mesocortical

Question 11

Why is the neurotransmitter glutamate implicated in schizophrenia?

Answer 11

There is reduced function of the NMDA glutamate receptor in schizophrenics, and dopamine is involved in this system as dopamine receptors restrict the release of glutamate

Question 12

What did Randrup and Munkvad do?

Answer 12

Created schizophrenic behaviour in rats by giving them amphetamines (activates dopamine production) and then reversed the effect by giving them neuroleptics (inhibits dopamine release)

Question 13

What did Iversen find?

Answer 13

Post-mortems on people who had schizophrenia found excess dopamine in the limbic system

Question 14

What do Lloyd et al. believe?

Answer 14

Even if dopamine is a causative factor, it may be an indirect factor mediated through environmental factors, because abnormal family circumstances can lead to higher dopamine levels which may in turn lead to the onset of schizophrenia

Question 15

What is the neural correlate explanation?

Answer 15

Abnormalities within specific brain areas may be associated with the development of schizophrenia

Question 16

What are ventricles?

Answer 16

Fluid-filled gaps between brain areas

Question 17

What should be considered when discussing neural correlates?

Answer 17

Whether brain abnormalities are caused by genetic factors or as a result of the disorder

Question 18

What does the neural correlates explanation see as the cause of positive symptoms of schizophrenia?

Answer 18

Overactive dopamine pathways in the mesolimbic area of the brain

Question 19

What does the neural correlates explanation see as the cause of negative symptoms of schizophrenia?

Answer 19

Underactive dopamine pathways in the mesocortical area of the brain

Question 20

What did Johnstone et al. find?

Answer 20

Schizophrenics had enlarged ventricles while non-sufferers did not, suggesting that schizophrenia is associated with a loss of brain tissue

Question 21

What did Weyandt et al. find?

Answer 21

Enlarged ventricles are associated with negative symptoms only, which implies enlarged ventricles cannot explain all symptoms and incidences of schizophrenia

Question 22

What did Hoek et al. find and what alternative biological explanation do they suggest?

Answer 22

Studied malnourished children in Holland after WWII and found that children born during or after the famine were 1.9/2.2 times more likely to develop schizophrenia; therefore suggests foetal malnutrition as the cause of schizophrenia

Question 23

What did Bennedson et al. find?

Answer 23

Women with schizophrenia were more likely to give birth to a child of low birth weight (a factor implicated in schizophrenia) because women with schizophrenia were more likely to be smokers, have substance abuse and alcohol problems which stunt intrauterine growth