AM - Schizophrenia II

Question 1

What is some evidence for psychosocial causes of schizophrenia? (5)

Answer 1

• Onset often occurs in adolescence.
• Stressful events can precipitate illness.
• Higher relapse rate in emotionally charged home environments.
• Blunted cortisol response in patients, showing an abnormal stress response.
• In normal response, salivary cortisol increases after stress, but this is blunted in schizophrenia.

Question 2

What structural brain changes are observed in schizophrenia? (4)

Answer 2

Some CAT and MRI studies show:
* Ventricular enlargement.
* Decreased volume of temporal lobe, especially the hippocampus.

BUT

• Lack of gliosis (no glial cell proliferation), indicating it’s not neurodegenerative.
• Limited cell death suggests brain cell destruction isn’t a primary cause.

Question 3

What cytoarchitectural abnormalities are seen in schizophrenia? (4)

Answer 3

• Abnormalities in the entorhinal cortex, including irregular neuron patterns.
• Fewer small neurons in superficial cortex layers; more large neurons in deeper layers.
• Schizophrenic cortex resembles preterm brain cortex, with excess unpruned synaptic connections.
• These abnormalities may relate to symptoms like hallucinations (excessive circuitry).

Question 4

How might viral infections be linked to schizophrenia? (2)

Answer 4

• Higher incidence in individuals born in late winter or spring, possibly due to seasonal viral infections.
• Hypothesis: maternal exposure to a virus in the second trimester may increase schizophrenia risk in the child.

This is one possible factor among others and not necessarily the sole cause.

Question 5

What is observed in dysfunctional limbic structures in schizophrenia? (2)

Answer 5

• Decreased size of the temporal lobe.
• Increased activity during auditory hallucinations.

Question 6

How does cerebral hemisphere dysfunction manifest in schizophrenia? (2)

Answer 6

• Left hemisphere, specialized for verbal function, shows disrupted lateralization in schizophrenia.
• In typical individuals, verbal tasks increase activity in the left hemisphere, but this pattern is altered in schizophrenia.

Question 7

What is the role of the dorsolateral prefrontal cortex in schizophrenia? (3)

Answer 7

• Shows hypofunctionality in schizophrenia.
• PET scans reveal reduced activity in this area, leading to disorganized thought and action.
• This “orchestra without a conductor” analogy highlights the lack of coordinated brain activity.

Question 8

What is the function of the basal ganglia in relation to schizophrenia? (2)

Answer 8

• Acts as a “gatekeeper” for motor control, learning, and emotional processing.
• It is also the primary site of action for antipsychotic medications.