schizophrenia Flashcards
what two criteria’s are used to diagnose sz?
DSM
ICD
what does DSM focus on?
positive symptoms, used in US and sometimes Britain
what does ICD focus on?
negative symptoms, used in Europe and majority of world
name some positive symptoms of sz?
hallucinations, delusions, speech disorganisation, catatonic behaviour
name some negative symptoms for sz?
speech poverty, avolition, affective flattening
what is reliability in the context of sz?
how consistent are the results,
inter-rater reliability - the extent to which different assessors agrees with the their assessment
two or more professionals arrive at the same diagnosis, e.g., sz
what is a study that shows the weakness of reliability in diagnosing sz?
Chenaiux - two psychiatrists independently diagnosis 100 people using DSM and ICD
inter-rater reliability was poor, 1st psychiatrist diagnosed 26 with DSM and 44 with ICD
2nd psychiatrist diagnosed 13 with DSM and 24 with ICD, poor reliability
what is validity in the context of sz?
the extent to which we are measuring what we are intending to measure, is it truly measuring
what studies show the weakness of validity in diagnosing sz?
Cheniaux - more likely to be diagnosed using ICD therefore under diagnosing in DSM showing poor validity
Rosenhan - pseudo patient study
what is co-morbidity?
two or more conditions occur together, if condition occur together then the validity is questioned
Buckley those diagnosed with sz also diagnosed with depression 50%, harder to classify and diagnose as it may be severe depression
what is symptom overlap?
when two or more conditions share symptoms
sz and bipolar disorder involve positive and negative symptoms, validity is questioned again.
ICD may diagnose them as sz whereas DSM diagnose them as bipolar
what is the biological explanation for sz?
genetics and neural factors play a role in sz
what is the genetic explanation for sz? evidence
twin studies showed the genetic link with family members.
100% DNA shared with MZ twins 50% DNA with DZ twins
candidate genes, individual genes associated with the risk of inheritance as sz is polygenic
studies have identified different candidate genes, sz is aetiologically heterogeneous, as different factors can lead to sz development
what did Ripke do and what were the results? biological
carried out a study combining previous data from genome-wide studies of sz
37,000 people DNA with sz compared to 113,000 controls.
108 genetic variations associated with the increased risk of sz
what is the dopamine hypothesis?
chemical messenger appear to work differently in the brain of a person with sz
dopamine is seen to be involved as it is important in several brain functions
hyperdopaminergia - high levels of dopamine leads to high activity in the subcortex
therefore excess dopamine in the brain associated with delusions and hallucinations