Schizophrenia Flashcards
What are the two main classification systems for sz?
DSM (diagnostic and statistical manual) mostly used in the US
ICD (international classification of disease) mostly used in Europe
(Both have been extensively revised over the years to reflect social changes and developments in psychology)
How has the DSM changed over the years?
1900 included 12 mental illnesses
Today 347 listed
(produced by American Psychiactric association)
Current edition DSM 5
Who is the ICD produced by?
WHO (world health organization)
10th edition
What are the diagnosis criteria for sz by the DSM 5?
For a diagnosis symptoms must have:
been present for at least 6 months
include at least one month of active symptoms
ruled out mood disorders (e.g. depression), drug abuse or brain tumours
Two of the required symptoms must be present
What is sz characterised by in the DSM?
Delusions, hallucinations, disorganised and behaviour and other symptoms that cause social and occupational dysfunction
What are the positive symptoms of sz?
Delusions, Hallucinations, Disorganised, Disorganised or catatonic (zoned out) behaviour
What are delusions?
Bizarre or grandiose beliefs that can seem real to the person with sz
Can be paranoid e.g. believing there’s a plot to kill them
What are hallucinations?
Distorted sensory experiences (not real)
Can come from any of the 5 senses
Often consist of voices commenting on their behaviour or telling them to things
What is disorganised speech?
Incoherent or loosely connected speech indicates disorganised thinking
What are the negative symptoms of sz?
Speech poverty, avolition, affective flattening
What is speech poverty?
Producing fewer words ad using a less coplex syntax
Delay in responses
Reduction in speech fluency and productivity reflects slowing or blocked thoughts
What is avolition?
Apathy: not able to initiate or persist in goal directed behaviour (e.g. sitting in the house for hours every day doing nothing)
Loss of motivation
Signs: poor hygiene, lack of energy/persistence
What is affective flattening?
a reduction in the range and intensity of emotional expression
What are positive symptoms?
Excess or distortion of normal functioning
What are negative symptoms?
Loss or a severe reduction of normal functioning
Why do we use classification systems?
classifications make it easier to identify, treat and break down the disorders
Should increase the reliability of diagnosis (Doctors are more likely to arrive at the same diagnosis using the same classification system)
What is reliability?
For a diagnosis to be reliable it must be repeatable
How is reliability tested?
Test-retest reliability: practitioner makes a consistent diagnosis on separate occasions from the same info
Inter-rater reliability: several practitioners make identical, independent diagnoses of the same patient
This level of agreement on diagnosis should be see over time and cross culturally
What did Keefe et al find?
Assesed sz cognition rating scale (SCoRS) applied to 79 patients with sz assessed at 3 academic research centres in the US
Demonstrated excellent test-retest reliability of about 0.90 (90% reliable) in various circumstances
What did Whaley find?
poor inter-rater reliability of classification systems: as low as 0.11 (11%)
What did Cheniaux find in relation to inter-rater reliability of classification systems?
Had 2 psychiatrists independently diagnose 100 patients using both the DSM and ICD criteria
Both diagnosed 2x as many with sz using ICD compared to DSM
One diagnosed twice as many with sz than the other
What are 3 possible reasons for the poor inter-rater reliability of sz diagnosis using classification systems?
-Clinical characteristics are open to interpretation e.g. as to the point when eccentricity becomes delusion
-The two system differ subtly:
DSM V requires 2 symptoms present for a month, ICD10 requires only one if its delusion
So symptom threshold is higher for DSM
-Cultural differences
What did Keith et al find (cultural differences in sz)?
2.1% African-Americans diagnosed with sz compared to 1.4% white Americans.
But African-Americans also more likely to suffer poverty or marital separation
What did Escobar suggest (racism in sz diagnosis)?
White psychiatrists may tend to over-interpret symptoms and distrust honesty of black people during diagnosis
What does the ethnic culture hypothesis suggest in terms of prognosis?
Predicts ethnic minorities experience less distress when diagnosed + living with a mental disorder because they live in more supportive social structures that don’t abandon them
What did Brekke and Barrio find?
support for ethnic culture hypothesis in their study of 184 individuals diagnosed with sz. Found white-Americans had more symptoms than ethnic minority groups
What is validity in terms of sz?
The extent to which sz is a unique syndrome with a shared set of characteristics distinct from other disorders.
The extent that a classification system such as ICD or DSM measures what it claims to measure
(diagnosis also can’t be valid if its not reliable)
What are the issues of validity of classification and diagnosis in sz?
Low reliability undermines validity
Symptoms, development of sz, repsonse to treatment all vary enormously
often difficult to define boundaries between sz and other disorders
What is gender bias?
The extent to which a diagnosis is dependent on the gender of the person
What did longnecker et al find?
reviewed studies of prevalence of sz- concluded that since the 1980s men have been diagnosed with sz more often than women…so:
Men may be more genetically vulnerable to sz?
Gender bias in diagnosis of sz?
What did Loring and Powell find in relation to gender bias of sz?
Randomly selected 290 male + female psychiatrists
Two case studies of patient’s behaviour:
56% diagnosed sz when patients described as ‘male’ (or no gender)
20% diagnosed sz when ‘female’
Gender bias less evident in female psychiatrists suggesting gender bias is also dependent on gender of the psychiatrist
What did Cotton et al suggest as a reason for gender bias?
Female patients typically function better than men-
more likely to work + have good family relationships
Could explain women’s lower diagnosis rate compared to men with similar symptoms
Better functioning may bias clinicians to under-diagnose due to:
Symptoms masked by higher functioning
Higher functioning makes case seem too mild for diagnosis
What s symptom overlap?
Where many symptoms of a disorder are also found within another disorder e.g. sz, bipolar and depression all overlap
most people with sz also have enough symptoms to receive another diagnosis
What is co-morbidity?
extent that two or more conditions occur together
if conditions occur together a lot of the time it calls into question their validity as separate disorders
sz commonly diagnosed with other conditions
What are the co-morbidity rates for sz? (Buckley et al)
50% also have diagnosis of depression
47% also have diagnosis of substance abuse
29% also have PTSD
24% also have OCD
(not a coincidence that 1% of pop. have sz and 2-3% pop. OCD but that they often occur together)
What is the problem with co-morbidity in sz?
Such high levels of co-morbidity pose a challenge to classification and diagnosis of sz:
if 1/2 sz also diagnosed with depression maybe we are bad at differentiating them
maybe in classification severe depression looks a lot like sz so are they on a continuum? are they one condition?
What are the differences in prognosis for those diagnosed with sz?
20% recover their previous level of functioning
10% achieve significant and lasting improvement
30% show some improvement with intermittent relapse
Diagnosis therefore has little predictive validity
What are the ethical issues of sz diagnosis?
Labelling: label of sz is permanent on medical records- not seen as curable, Scheff highlighted possibility of self fulfilling prophecy ‘living the label’
other people are also often suspicious of such labels
What biological factors may affect sz?
genetic pre-disposition, neural correlates, early life factors e.g. pregnancy complications as well as environmental stressors such as drug use
What are the methods for studying genetic the factors of sz?
Family studies, twin studies, adoption studies
What are neural correlates?
The connection between brain structure/ function and symptoms of sz)
What have family studies shown about sz as a genetic disorder? (genetic factors of sz)
Family studies have established that sz is more common in those with genetic relatives who have sz (closer relation= more likelihood of sz)
What did Gottesman’s study into family genetic component of sz find? (genetic factors of sz)
Children with 2 sz parents- concordance rate of 46%
Children with 1 sz parent- 13%
Children with sz sibling- 9%
What did Gottesman’s twin study meta-analysis find? (genetic factors of sz)
Summarised 40 twin studies and found that if 1 twin had sz concordance rate was:
48% MZ twins
17% DZ twins
Suggests likelihood of sz has a large genetic component
Why are adoption studies used in psychology? (genetic factors of sz)
In order to separate genetic and environmental influences for those that share genes
