schizophrenia Flashcards
(60 cards)
define schizophrenia
group of psychotic disorders that are characterised by a loss of contact with reality
features of schizophrenia
- prevalence rate of 1%
- typically begins in late teens or early 20s
- episodic illness- period of psychotic disorders as well as normal functioning
- starts with low mood or anxiety, and active phase follows with specific symptoms
- psychotic episodes can last from 1-6 months to a year
- 2/3 make substantial progress
- can be acute (sudden) or chronic (gradual)
define positive symptoms
reflects an excess of distortion of normal functions
positive symptoms of schizophrenia
- hallucinations- perceptual disturbances, including auditory and visual
- delusions- believing things aren’t true
-disorganised speech- echolalia, nonsense of gibberish
define negative symptoms
reduction or loss of normal functions
negative symptoms of schizophrenia
- speech poverty/alogia- reduction in quality and amount of speech
- avolition- lack of desire or motivation for anything
- affective flattening- loss of expression and emotional response, unexpected emotions
- anhedonia- lack of pleasure seeking behaviours
- catatonic behaviour- affect a persons ability to speak, move or respond to their environment, motionless, frantic movements
diagnosis of schizophrenia
- DSM states they must show at least two of delusions, hallucinations, disorganised speech, catatonic behaviour or any negative symptoms- one from the first 3
- must be present for at least 6 months
- subtypes are not recognised in DSM-V- paranoid, disorganised or catatonic
how are mental disorders diagnosed
- DSM 5 is the american manual used to classify and describe over 200 disorders
- ICD 100 is used in Europe
define reliability
consistency in how the classification system produces the same diagnosis for a particular set of symptoms
define inter rated reliability with schizophrenia
different clinicians give identical diagnosis to the same patient
define test retest reliability in terms of schizophrenia
diagnosis is consistent over time using the same information
evaluation of reliability of diagnosis strengths
+ help provide clinicians with common language, permitting communication
evaluation of reliability of diagnosis weaknesses
- experienced psychiatrists only agree 54% as seen by Beck et al and inter rater reliability correlation found as low as 0.11
- misinterpretation and subjective as “bizarre delusions” can be interpreted differently- found with psychiatrists in US who only had inter rated reliability of 0.4 when differentiating
- variation between countries- new york psychiatrist twice as likely to diagnose schizophrenia than london, who were 2x more likely to diagnose depression
- test retest reliability is low- 37% concordance rate
=> however improv,events with cognitive screening like RBANS found test retest reliability to be as high as 0.84
define validity and the different types
how accurately is schizophrenia diagnosed and that the classification system measures what it intends to measure
aetiological- extent to which cause of schizophrenia is the same
descriptive- extent to which individuals diagnosed with the same disorder are similar
predictive- extent to which diagnostic categories predict the outcome of treatment
define symptom overlap
extent to which a symptom appears in more than one disorder
- bipolar disorder and schizophrenia both share delusions and avolition as a symptom
define comorbidity
presence of one or more additional disorders co-occurring with primary disorder, like anxiety and depression commonly occurring with schizophrenia
evaluation of validity of schizophrenia diagnosis strengths
+ more modern system show greater validity
+ diagnostic categories are justifiable and give clinicians an agreed framework to work so effective therapies can be developed
evaluation of validity of schizophrenia diagnosis weaknesses
- too many variations of outcome as 20% recover and may never have an episode whereas 10% may commit suicide
- rosenhan used pseudo patients in a psychotic unit and once admitted, they behaved normally but staff at the unit still noted their behaviour as symptoms
- symptom overload and comorbidity makes it hard- 50% of patients also had depression
- gender bias- castle et al argues criteria is too strict as rate of schizophrenia in men was 2x more than women, also found that administer of oestrogen reduces schizo symptoms
- culture bias- afro-caribbean are diagnosed more with schizophrenia than white people, despite same rate of diagnosis within the caribbean (8x higher), or perhaps stressors in britain like racism increases rate of schizo
evaluation of symptoms overlap
+ ellason and ross found those with DID have more symptoms of schizophrenia than people actually with it
- makes it difficult for clinicians to diagnose
- misdiagnosis can lead to delay in receiving treatment
evaluation of comorbidity
+ buckley estimates comorbid depression occurs in 50% of sufferers
- difficulty in validity of diagnosis
- leads to less effective treatments and lower levels of functioning
- sufferers with comorbid disorders are generally excluded from research but for, majority of patients
- high levels of co-morbidity could be evidence for separate sub types of schizophrenia
how can genetics explain schizophrenia
- research uses twin and family studies to look at concordance rates
- gene mapping studies have been used to find genetic material among sufferers
- adoption studies help to entangle genes and environment
evaluation of genetics to explain schizophrenia strengths
+ concordance rate in MZ twins was 40% compared to 7% for DZ
+ Gurling found chromosomes 8p21-22 and PCM1 gene in schizophrenia sufferers
+ study with adopted children found those with biological mothers with schizo we’re more likely to develop it
evaluation of genetics to explain schizo weaknesses
- study into 164 women who had children adopted away found 14 adoptees developed schizophrenia showing being reared into a healthy adoptive family had a protective effect
- diathesis stress model and other factors
- socially Mz twins can be treated the same and thus more likely to be concordant
- concordance rate not 100% for MZ twins
how can dopamine hypothesis explain schizophrenia
- too much dopamine can lead to onset of schizophrenia as it causes hallucinations and delusions (hyperdopaminergia)
- thought to have abnormally high number of D2 receptors, resulting in more dopamine binding
- recently, also found high levels of dopamine in NAC ads associated with positive symptoms, and deficit in VTA associated with negative (hypodopaminergia)