intro to SZ + biological explanations Flashcards
schizophrenia is
a severe mental illness where contact with reality and insight are impaired.
Often people with the illness will experience psychosis.
Affects approx. 1% of the population and is more commonly diagnosed in men.
more common in cities and working class
positive symptoms
additional experiences that go beyond normal experiences. They add to behaviour.
negative symptoms
loss of usual abilities and experiences. They ‘take away’ from behaviour.
positive symptom: hallucinations
experience stimuli that have no basis in reality
can be visual, auditory, olfactory (smelling)
positive symptom:
delusions
beliefs that have no basis in reality
delusions of grandeur - false impression of own importance eg. thinking you’re a famous politician
delusions of persecution - feeling that they are being harmed in some way eg. think you’re being targeted by government.
negative symptom: avolition
loss of motivation to carry out tasks - ‘apathy’
characterised as poor hygiene, lack of engagement in education, lack of energy
negative symptom: speech poverty
problems with speech. Can include reduced frequency, reduced quality, delayed responses
speech disorganisation is when speech becomes incoherent/changed topic mid sentence
symptoms used for diagnosis
ICD-10 = 2+ negative symptoms must be present for diagnosis
DSM-5 = 1+ positive symptoms must be present for diagnosis
both recognise there are subtypes of SZ but this has been dropped by DSM-5
subtypes of SZ
paranoid: powerful dellusions/hallucinations and few other symptoms
Hebephrenic: mainly negative symptoms
Catatonic: disturbance to movement; immobile or overactive
co-morbidity
when a person has 2 or more diagnoses alongside each other. E.g. they have a diagnosis of Schizophrenia and Depression. They will be treated for both of their diagnoses.
symptom overlap
when a disorder has similar symptoms to another disorder. E.g. having the negative symptom of avolition and symptoms of depression. They are very similar.
limitation of diagnosing - issues w reliability
E: definition! Cheniaux et al found one psychiatrist diagnosed 26/100 patients with SZ using DSM5 and 44/100 using ICD-10. Another diagnosed 13/ same 100 patients with DSM and 24 with ICD
C: low inter rater reliabilityfor diagnosing SZ between professionals. So, people may be inaccurately diagnosed or some people won’t be diagnosed even if they’re showing a symptom.
limitation of diagnosing - issues w validity
E: in Cheniaux’s study, SZ more likely to be diagnosed with ICD-10 as a psychiatrist diagnosed 44/100 with it vs 26/100 with DSM-5.
C: SZ more likely to be diagnosed with ICD as it uses negative symptoms which are more common. so, diagnosis changed when using different tools, and will potentially be overdiagnosed with ICD-10 and underdiagnosed with DSM-5. this is criterion validity.
limitation with diagnosis - gender bias
E: since 2980s men diagnosed with SZ more than women. Clinicians may just believe women are ‘hysterical females’ or exaggerating so they don’t consider their symptoms (alpha bias)
C: underdiagnosis of women means they may be suffering and not get help so they would have poorer QOL eg, not social, no job
limitation with diagnosis - culture bias
E: people with Afro caribbean origin more likely than white people to be diagnosed despite rates of SZ in Africa+Caribbean not being high. Because, in their cultures speaking to dead relatives is a positive religious experience not a symptom. Also, DSM made by American psychologists so different ideals.
C: overdiagnosis of ethnic minorities means they are being treated for something they don’t have eg. drug therapy.
HOWEVER in most recent DSM, there is an insert that highlights possible cultural differences.
genetic basis of SZ
Gottesman’s research
conducted twin studies and found strong concordance rates
MZ twins - 48% risk
DZ twins - 17% risk
general pop - 1% risk
his research demonstrates there is a genetic basis for SZ. Concordance rates higher for MZ twins
candidate genes
researchers found small number of genes responsible for SZ - polygenic
Ripke et al found 108 genetic variations associated with increased risk of SZ
COMT gene codes for functioning of neurotransmitters eg. dopamine
the dopamine hypothesis
dopamine transmits messages between neurons
dopamine works differently in people with SZ
it’s particularly important in the functioning of several brain systems that cause symptoms of SZ - in particular cortex + subcortex
