Biological explanations Flashcards
What did Gottesman’s 1991 study find about schizophrenia in twins?
The concordance rate is 48% for monozygotic (identical) twins and 17% for dizygotic (fraternal) twins, suggesting a genetic component.
Why is schizophrenia not entirely genetic?
Since the concordance rate is not 100%, environmental factors also play a role (diathesis model)
What are candidate genes in schizophrenia?
Schizophrenia is polygenic, meaning multiple genes contribute, especially those linked to dopamine regulation.
What did Ripke’s study find about genetic risk factors for schizophrenia?
Identified 108 genetic variations associated with a slightly higher risk of developing schizophrenia.
What does it mean if something is aetiology heterogenous?
It has several root causes.
How does parental age influence schizophrenia risk?
Schizophrenia can arise from new genetic mutations, even in individuals with no family history of the disorder.
Why is there a higher risk in older paternal age for schizophrenia?
Older paternal age (50+) increases schizophrenia risk due to sperm mutations.
What is the original dopamine hypothesis of schizophrenia?
Schizophrenia is caused by excess dopamine activity (hyperdopaminergia) in the brain.
Excess dopamine receptors in pathways from the subcortex to Broca’s area.
May explain speech poverty and/or auditory hallucinations.
How was the dopamine hypothesis updated?
Dopamine levels are abnormal in different brain areas
Low dopamine levels (hypodopaminergia) in the prefrontal cortex (responsible for thinking and decision-making) lead to cognitive impairments, avolition, and speech poverty.
This low dopamine activity then triggers excess dopamine release in subcortical areas, worsening hallucinations and delusions.
This explains why both too much and too little dopamine contribute to schizophrenia symptoms.
