Schizophrenia - Biological Explanations: Structural Abnormalities

Question 1

What are the 3 structural abnormalities that are used to explain schizophrenia

Answer 1

• Brain ventricles
• Cortical Atrophy
• Reversed Cerebral Asymmetry

Question 2

How does brain ventricles explain schizophrenia

Answer 2

• Brain ventricles are fluid-filled cavities within the brain responsible for producing and containing cerebrospinal fluid (CSF), which cushions the brain and helps remove waste products.
• In schizophrenics, there is often an enlargement of the lateral and third ventricles.
• This indicates a loss of brain tissue surrounding these ventricles = thought to reflect neurodegenerative changes associated with the disorder

Question 3

How does cortical atrophy explain schizophrenia

Answer 3

• Cortical atrophy refers to the loss of neurons and the shrinkage of the cerebral cortex, which is the outer layer of the brain responsible for higher cognitive functions. Also results in widening of sulci covering cerebral cortex
• cortical atrophy is commonly observed in the prefrontal cortex and temporal lobes. This atrophy is associated with deficits in executive functions, memory, and cognitive processing.
• found in 20-35% of people with chronic schizophrenia

Question 4

How does reversed Cerebral Asymmetry explain schizophrenia

Answer 4

• Cerebral asymmetry refers to the functional differences between the left and right hemispheres of the brain.
  Normally:
• left hemisphere = dominant for language and analytical tasks
• right hemisphere = involved in spatial and holistic processing.
  In schizophrenics
• the right hemisphere may show increased activity or structural abnormalities in areas typically dominated by the left hemisphere in healthy individuals.
• this is associated with the cognitive and perceptual disturbances in schizophrenia.

Question 5

What are the 4 supporting evidences

Answer 5

• Weinberger et al (1979)
• Andreason (1988)
• Vita et al (1988)
• Luchins et al (1979)

Question 6

In Weinberger et al (1979): Did? Found? How it supports explanation

Answer 6

• did CAT scans and found ventricular size greater in 58 SZ than in 56 in control group
• shows a link between enlarged ventricles and the symptomatology in SZ
• this research was highly scientific (used CAT scans to produce objective data) = high in internal validity
• COUNTER: don’t know if structural abnormalities is due to medication rather than the schizophrenia itself. This confounding variable therefore lowers the validity

Question 7

In Andreason (1988): Did? Found? How it supports explanation

Answer 7

• did MRI scans and found SZ had ventricles 20-50% larger than controls
  -shows a link between enlarged ventricles and the symptomatology in SZ
• COUNTER: didn’t investigate a causal relationship = only an observation

Question 8

In Vita et al (1988): Did? Found? How it supports explanation

Answer 8

• did CAT scans and found 124 SZ and 45 control group to have moderate to severe atrophy
• shows a link that cortical atrophy is associated with some SZ but not all
• therefore this is weak supporting evidence and is low in useful application because there is little that can be done with these results

Question 9

In Luchins et al (1979): Did? Found? How it supports explanation

Answer 9

• did CAT scans if right handed individuals with SZ and without. Found increased frequency of reversed cerebral Asymmetry in schizophrenics
• it supports the explanation because the reversals were more common in Schizophrenics, suggesting a link between this structural abnormality and schizophrenics
• COUNTER: Sample is extremely constrained to only right handed schizophrenics

Question 10

What is a PET scan

Answer 10

• Positron Emission Tomography (PET) scans measure brain activity by detecting radiation from injected radioactive tracers that bind to specific molecules.

Question 11

What are MRIs

Answer 11

Magnetic Resonance Imaging (MRI) uses strong magnetic fields and radio waves to create detailed images of brain structure

Question 12

What are fMRIs

Answer 12

Functional Magnetic Resonance Imaging (fMRI) measures brain activity by detecting changes in blood flow and oxygenation levels.

Question 13

What are CAT scans

Answer 13

Computed Tomography (CAT) scans use X-rays to create cross-sectional images of the brain, which can be combined to form a 3D view.

Question 14

What are the contradictory evidences

Answer 14

• McCarley et al (1999)
• Lyon et al (1981)
• Roy et al (1998)
• Mathalon et al (2003)

Question 15

How would contradictory evidence from McCarley et al (1999) disprove the structural abnormalities explanation for schizophrenia

Answer 15

P: McCarley et al (1999) challenge the reliability of ventricular enlargement as a consistent marker for schizophrenia.
E: found that while some patients with schizophrenia show enlarged ventricles, this feature is not present in all individuals diagnosed with the disorder.
T: This contradicts the structural abnormalities explanation by suggesting that ventricular enlargement is not a universal or definitive feature of schizophrenia. Therefore this explanation has low reliability

Question 16

How would contradictory evidence from Lyon et al (1981) disprove the structural abnormalities explanation for schizophrenia

Answer 16

P: Lyon et al (1981) offer evidence suggesting that the structural abnormalities found in schizophrenia could be a result of medication rather than the disorder itself.
E: found that as doses of antipsychotics increased the density of brain tissue decreased
T: This contradicts the structural abnormalities explanation by implying that the brain changes observed in schizophrenia may not be inherent to the disorder but rather a consequence of prolonged antipsychotic use. Therefore reducing the explanations reliability

Question 17

How would contradictory evidence from Roy et al (1998) disprove the structural abnormalities explanation for schizophrenia

Answer 17

P: Roy et al (1998) found evidence that challenges the notion that structural abnormalities are exclusive to schizophrenia.
E: found individuals with bipolar disorder and schizoaffective disorder both has enlarged ventricles
T: If the abnormalities are not specific to schizophrenia, it raises questions about their role as a causal factor in the disorder.

Question 18

How would contradictory evidence from Mathalon et al (2003) disprove the structural abnormalities explanation for schizophrenia

Answer 18

P: Mathalon et al (2003) question the causality of structural abnormalities in schizophrenia, proposing an alternative explanation.
E: found that structural brain changes in schizophrenia, such as cortical atrophy and ventricular enlargement, may result from the disorder’s progression rather than being present from its onset.
T: If these abnormalities are not present at the onset of schizophrenia, it weakens the argument that they are a primary cause of the disorder’s symptoms. Therefore showing the problem of the explanation not being based on any causal evidence

Question 19

Evaluate the explanation for being deterministic

Answer 19

P: it’s deterministic as it suggests that changes in brain structure, such as ventricular enlargement and cortical atrophy, are responsible for the development of the disorder.
E: supported by research such as Weinberger et al (1979), who found that patients with schizophrenia had significantly enlarged lateral and third ventricles compared to healthy controls
T: This deterministic perspective is beneficial because it provides a clear, biological cause for the disorder, which allows for more precise diagnostic tools and targeted medical interventions
COUNTER: could have a demoralizing effect on patients’ recovery if they Believe their SZ are solely determined by unchangeable brain abnormalities could lead to feelings of helplessness, which might undermine motivation to engage in recovery/treatment

Question 20

Evaluate the explanation for being reductionist

Answer 20

P: reductionist as it simplifies the complex nature of schizophrenia by focusing on specific brain structure abnormalities. This makes the disorder easier to understand and diagnose.
E: For example, Vita et al (1988) used MRI scans to identify significant ventricular enlargement and reduced gray matter volume in patients with schizophrenia.
T: This reductionist approach allows clinicians to potentially diagnose schizophrenia based on measurable brain abnormalities, offering a more objective diagnostic criterion compared to relying solely on subjective symptom reporting.
COUNTER: This narrow focus risks providing an incomplete picture, leading to treatments that may not address the full complexity of the individual’s because it ignores social, cognitive and cultural factors

Question 21

Evaluate the usefulness of this explanation

Answer 21

P: While identifying brain abnormalities such as enlarged ventricles or cortical atrophy can aid in diagnosis, the explanation does not always translate into effective or accessible treatments
E: Vita et al (1988) showed progressive brain atrophy in schizophrenia patients, but this finding doesn’t directly lead to a specific cure or intervention that halts or reverses this atrophy.
T: because the structural changes in the brain are often already present by the time schizophrenia is diagnosed, interventions based solely on these abnormalities may be too late or insufficient to address the disorder’s full range of symptoms.
FURTHERMORE: perhaps holistic treatments such as CBT (that are based on the social/cultural explanations of SZ) might be a more useful

Question 22

Evaluate the explanation for being scientific

Answer 22

P: The explanation relies on objective, measurable data from scanning techniques which provide precise, detailed images of brain structures
E: Vita et al (1988) used MRI scans to identify brain abnormalities such as cortical atrophy
T: This reliance on objective data ensures that the findings are reliable and valid which lends high credibility and accuracy to the explanation
COUNTER: cause and effect cannot be established through correlational findings alone. Without experimental evidence, we can’t determine whether the abnormalities found in the brain are the primary cause of schizophrenia or secondary consequences of living with the disorder, its treatments, or other environmental factors