biological explanations for schizophrenia

Question 1

Genetic Explanation

Answer 1

Schizophrenia has a genetic component.

Gottesman (1991) found a higher concordance rate for schizophrenia in MZ twins (48%) than DZ twins (17%) and the general population (1%)

Question 2

Dopamine Hypothesis

Answer 2

Hyperdopaminergia in the subcortical areas of the brain (e.g. basal ganglia) leads to positive symptoms (e.g. hallucinations, delusions).

Hypodopaminergia in the prefrontal cortex leads to negative symptoms (e.g. flat affect, avolition)

Question 3

Neural Correlates

Answer 3

Enlarged ventricles: Found in patients with more severe negative symptoms.

Auditory cortex overactivity: Correlates with the auditory hallucinations seen in schizophrenia patients

Question 4

strengths

Answer 4

✅ Strong supporting evidence
→ Example: Gottesman (1991) found a 48% concordance rate for MZ twins, compared to 17% for DZ twins.

✅ Large-scale genetic studies
→ Example: Ripke et al. (2014) found 108 genetic variations associated with schizophrenia risk

Question 5

limitations

Answer 5

❌ Concordance not 100%
→ Example: Even MZ twins don’t both develop schizophrenia — suggesting environmental factors too.

❌ Reductionist
→ Example: Focuses solely on genes, ignoring psychological, social, or environmental influences