Schizophrenia - Explanations Flashcards
what genes can help cause schizophrenia?
dopamine receptor genes (D2)
glutamate receptor genes (AMPA)
what are the 3 types of studies into genetic factors in developing schizophrenia?
family
twin
adoption
describe a family study into developing schizophrenia?
concordance rates investigated in children with SZ parents or siblings - combination of biological and environmental factors
what was the results for the family study into developing SZ?
2x SZ parents - 46% concordance rate
1x SZ parent - 13% concordance rate
1x SZ sibling - 9% concordance rate
describe a twin study into developing SZ?
meta analysis on identical vs non-identical concordance rates for SZ
what was the results for the twin study into developing SZ?
identical - 40%
non-identical - 7%
what is an issue with the twin study into developing SZ?
many studies knew the a twin had SZ - investigator bias
describe an adoption study into developing SZ?
compared adoptees with SZ biological mother vs non-SZ bio mother
what were the results from the adoption study into developing SZ?
6.7% with SZ mothers developed SZ
2% without developed SZ
what is the dopamine hypothesis?
SZ caused by imbalances of dopamine:
hyperdopaminergia in mesolimbic pathway
hypodopaminergia in prefrontal cortex
describe how the dopamine hypothesis explains positive and negative symptoms
hyperdopaminergia in mesolimbic pathway causes positive symptoms, but uses up all the dopamine so by the time it reaches the prefrontal cortex there is too little dopamine - causing negative symptoms
what are some advantages of the dopamine hypothesis?
research support - tienari adoption study, grilly study (patients with wrong dosages)
ecological validity/applications - drug therapies
what are some disadvantages of the dopamine hypothesis?
biologically reductionist - ignores environmental triggers - thought that it is a result of diathesis stress not just biology
drug therapies based off dopamine hypothesis doesn’t help 1/3 patients
correlation vs causation
describe the grilly 2002 study
parkinsons patients with wrong dosage of drug developed SZ symptoms
all drug does in increase dopamine, so therefore dopamine causes SZ symptoms
who suggested the dopamine hypothesis?
davis + khan
what are the psychological explanations of schizophrenia?
double bind theory
expressed emotion
what is the double-bind theory?
says contradictory messages from parents can cause children to become schizophrenic as they cannot form construct coherent reality
eg mother saying she loves you while hitting you
what is the expressed emotion theory?
families with high emotional expression and hostility can trigger schizophrenia in people vulnerable to it
what research supports the expressed emotion theory?
expressed emotion in friends/family strongly correlated with relapse rates
these families describe SZ relatives in hostile terms
found that negative emotions can trigger SZ episodes, supportive families can help prevent
what is the cognitive explanation for delusions?
inadequate information processing
leads to egocentric bias
leads to failure to contextualise events
patients unable to perform ‘reality testing’
what is the cognitive explanation for hallucinations?
hypervigilance
higher expectancy of voices
can’t distinguish between sensory info and internal images
missatribute source of internal images to external sources
failure to reality check properly so don’t see disconfirming evidence
how does the biological explanation link to the cognitive explanation of delusions and hallucinations?
cognitive processing bias - hyperdopaminergia in/around mesolimbic pathway
misattribution of consequences to causes - hypodopaminergia in prefrontal cortex and ACC
failure to test reality - DLPFC and hippocampus links to atrophy or dysfunction
define dyfunctional thought processing
cognitive habits / beliefs that cause an individual to evaluate information inappropriately and produce undesirable consequences
what are the advantages of the family dysfunction explanations?
supports diathesis-stress, supported by Tienari
high correlation between EE households and relapses
what are the disadvantages of the family dysfunction theories?
not all patients that live in EE households relapse - determinist - ignoring individual differences with stress responses