Biological Explanations For Schizophrenia

Question 1

What three biological explanations are there for schizophrenia?

Answer 1

• genetics
• dopamine hypothesis
• neural correlates

Question 2

Outline the genetic explanation for schizophrenia?

Answer 2

-Schizophrenia is inherited and a genetic variation may predispose an individual to develop schizophrenia

• Twin studies, family studies and adoption studies are used to find out if genetics cause schizophrenia.
• It is a polygenic theory which means it is thought that a combination of individual genes can cause schizophrenia and usually these genes are associated with altered levels of dopamine.

Question 3

AO3 for genetic explanation for schizophrenia?

Answer 3

Gottseman:

• meta analysis
• MZ: 54% DZ:12%

Question 4

Outline the dopamine hypothesis?

Answer 4

-Dopamine is a neurotransmitter responsible for the sensation of pleasure, high levels are associated with schizophrenia

• neurones firing at a faster rate than usual due to an excess of dopamine lead to hallucinations and delusions.
• schizophrenics are suggested to have too many D2 receptors In certain areas of the brain which dopamine binds onto and the increased amount of D2 receptors allow for more dopamine to bind onto the post synaptic neurone causing more neurones to fire action potential. However high levels of dopamine only cause the development of positive symptoms.

-It is also suggested that Schizophrenics can have lower levels of dopamine, which can cause the development of negative symptoms.

Question 5

Outline leucht et al’s research supporting dopamine hypothesis

Answer 5

• Leucht et al conducted a meta analysis on studies which involved investigating the effect antipsychotics had on schizophrenics compared to a placebo treatment
• Antipsychotics regulate the levels of dopamine in the brain
• it was found all antipsychotics were more effective compared to the placebo in all studies
• since the antipsychotics which regulated dopamine were effective to treat schizophrenics, it must be caused by altered levels of dopamine.

Question 6

Outline the neural correlates explanation for schizophrenia?

Answer 6

-This explanation suggests that the experiences schizophrenics have and the cause of the disorder is the structure and function of the brain.

• Deficits in certain areas of the brain cause positive or negative symptoms to occur.
• Deficits in the ventrial striatum is an area responsible for the anticipation of a reward therefore contributing to motivation levels, negative symptoms involved with motivation such as abolition then develop
• Lower activities in the superior temporal gyrus and the anterior cingulate gyrus will cause an individual to experience positive symptoms such as hallucinations as this part of the brain is responsible for auditory processing.
• enlarged ventricles are associated with damage to the pre frontal cortex and central areas of the brain and schizophrenics are more likely going to have enlarged ventricles.

Question 7

AO3 for neural correlates

Answer 7

• Allen provides research evidence supporting the neural correlate explanation for schizophrenia
• they scanned the brains of schizophrenics who had auditory hallucinations and compared them to a control group.
• Allen found that they’re were lower levels of activity in the superior temporal gyrus and anterior cingulate gyrus regions in the schizophrenic patients brains.
• Therefore this supports the idea that the structure and function of the brain can cause schizophrenia to develop.