schizophrenia Flashcards
prevalence of Sz
-affects 1% of population
-more common in males
-more common in lower socio economic groups
diagnosis of Sz
-linked to classification
-classification=identify symptoms that go together and make one disorder
-diagnosis= identify symptoms and use classification to identify the disorder
DSM-5 and ICD-10 differ
2 main classification systems
DSM-5=one positive symptom must be present
ICD-10=not used for diagnosis until 2022- two or more negative symptoms are suffiecient for diagnosis
what are positive symptoms
-additional experiences beyond those of ordinary existence
pos symptoms- hallucinations
-unusual sensory experiences that have no basis in reality
-distorted perceptions of real thing-e.g. hearing voices or seeing people who arent there
pos symptoms-delusisons
-beliefs that have no basis in reality, make them behave in ways bizzare to others
-e.g important person or victim of conspiracy
negative symptoms
-loss of usual abilities and experiences
neg symptoms- speech poverty
-a reduction in amount and quality of speech
-may include speech delay
-DSM emphasises speech disorganisation and incoherence as pos symptom
neg symptoms- avolition
-severe loss of motivation to carry out everyday tasks
-results in low activity levels and unwillingness to carry out goal directed behaviour
bio explanations-genetic basis- family studies
-strong relationships between degree of genetic similarity and shared risk of Sz
Gottesman (1991) large scale study
-someone with aunt with Sz has a 2% chance
-9% for sibling
-48% for identical twin
-family members also share environment but this indicates genetic basis
bio explanation-genetic basis-candidate genes
-unsuccessful to find single genetic variation for schizophrenia
-Sz is polygenic (requires several genes)
-also aetiologically heterogeneous (risk affected by different combos)
-Ripke et al (2014) combined data from previous studies, found 108 seperate genes associated with increased risk of Sz
bio explanations- genetic basis- mutation
-Sz can have genetic origin in family history because of mutation in parental DNA
-correlation between parental age (risk of sperm mutation) and inc risk of Sz (Brown et al 2002)
bio explanations-neural correlates- role of dopamine
-dopamine (DA) widely believed to be involved in Sz because it is featured in functioning of brain systems related to Sz symptoms
bio explanations- neural correlates- original DA hypothesis (hyperdopaminergia)
-linked to subcortex
-high dopamine activity in subcortex associated with hallucinations and poverty of speech
-may explain specific sympytoms
bio explanations- neural correlates- updated version (hypodopaminergia)
-linked to prefrontal cortex
-added low levels of DA in prefrontal cortex, could explain neg symptoms
-explains origins of abnormal DA- genetic variations and early experiences of stress make some more sensitive to cortical hypo- and hence subcortical hyper
(howes et al)
psych explanations- family dysfunction-schizophrenic mother
-rejecting and controlling
-Fromm Reichmann (1948) mothers who cause Sz
-mothers are cold, rejecting and controlling, create climate of tension and secrecy
-leads to distrust and paranoid delusions (sz)
psych explanations- family dysfunction- double bind theory
-conflicting family communication
-Bateson et al (1972)
-child regularly told they are wrong but conflicting messages about what is wrong
-cannot express feelings for the situation
-child punished with withdrawl of love
-think world in dangerous, leads to delusions
psych explanations- family dysfunction- expressed emotion
-EE is the level of mainly negative emotion expressed including
1.verbal criticism of person with Sz
2.hostility to them
3.over involvement in their life
-high EE triggers person, may trigger onset or relapse
psych explanations- cognitive explanations- dysfunctional thought processing
-low levels of info processing suggest cognition is impaired
-E.g. reduced processing in vental striatum associated with neg symptoms
psych explanations- cognitive explanations- Metarepresentation
-the cognitive ability to reflect on thoughts + behaviours (Frith 1992)
-leads to hallucinations
-disrupts ability to recognise thoughts as our own (hallucinations)
-thought insertion delusions
psych explanations- cognitive explanations- central control dysfunction
-leads to speech poverty
-Frith et al (1992) dysfunction of central control as a way to explain speech poverty
-people with Sz experience derailment of thoughts because each word triggers associations they cannot suppress
