biological explanations of SCZ Flashcards
What are the biological explanations for schizophrenia?
Genetics and neural correlates including the dopamine hypothesis
How do genetic factors contribute to schizophrenia?
Schizophrenia tends to run in families and research suggests a genetic predisposition increases the likelihood of developing the disorder
What are neural correlates in the context of schizophrenia?
Neural correlates are patterns of brain activity or structures associated with the symptoms of schizophrenia
What is the dopamine hypothesis of schizophrenia?
The dopamine hypothesis suggests that schizophrenia is linked to an overactivity of dopamine in certain brain regions
Which brain areas are implicated in the dopamine hypothesis?
The mesolimbic and mesocortical pathways are key areas involved in dopamine overactivity
How is dopamine overactivity related to positive symptoms of schizophrenia?
Excess dopamine in the mesolimbic pathway is thought to cause positive symptoms like hallucinations and delusions
How is dopamine underactivity related to negative symptoms of schizophrenia?
Reduced dopamine in the mesocortical pathway is associated with negative symptoms such as avolition and flat affect
What evidence supports the genetic basis of schizophrenia?
Twin studies family studies and adoption studies have shown higher concordance rates for schizophrenia among individuals who share more genetic material
What are the key neurotransmitters involved in schizophrenia?
Dopamine and more recently glutamate has also been implicated
What type of studies are used to investigate the genetic basis of schizophrenia?
Twin studies family studies and adoption studies are commonly used
What is the role of the prefrontal cortex in schizophrenia?
The prefrontal cortex involved in decision-making and reasoning shows reduced activity in individuals with schizophrenia contributing to cognitive symptoms
What structural abnormalities are associated with schizophrenia?
Enlarged ventricles reduced grey matter and abnormalities in the temporal and frontal lobes
How does the glutamate hypothesis relate to schizophrenia?
The glutamate hypothesis suggests that schizophrenia may involve reduced glutamate activity particularly in the prefrontal cortex
(Evidence for genetic links in SCZ)
What did Shields (1962) find regarding schizophrenia?
Shields found higher concordance rates for schizophrenia in monozygotic twins (MZ) compared to dizygotic twins (DZ) supporting a genetic basis
(Evidence for neural correlates)
What did Johnstone et al. (1976) find regarding brain structure and schizophrenia?
Johnstone et al. found that individuals with schizophrenia had enlarged ventricles in the brain suggesting a link between structural abnormalities and the disorder
What did Gottesman et al. (1991) find about genetic risk for schizophrenia?
Gottesman et al. found that the risk of developing schizophrenia increases with genetic relatedness to an affected individual with concordance rates highest in monozygotic twins
Evidence against genetic explanations of SCZ.
No study has found a 100% concordance rate between MZ twins, so SCZ cant just be caused by genes.
Other factors must be considered
Evidence for dopamine hypothesis.
Antipsychotic drugs reduce the symptoms of SCZ by blocking D2 receptor.
drugs such as amphetamines, which increase dopamine function can sometimes cause SCZ like symptoms in people witout SCZ
Evidence against dopamine hypotheses.
Antipsychotics only work on positive symptoms of SCZ.
Link with dopamine is correlational so it doest show cause and effect relationship.
Evidence against neural correlates.
people without SCZ can also have enlarged ventricles.
findings are correlational/
