Schizophrenia: Classification and Symptoms Flashcards
What is the difference between positive and negative symptoms?
Positive: appear to reflect an excess or distortion of normal functions
Negative: reflect a loss of normal functions
Name 2 positive and 2 negative symptoms
Positive: hallucinations/delusions
Negative: avolition (reduction of goal orientated behaviour)/ affective flattening (reduction in range and intensity of emotional expression)
What are the two means of testing reliability?
1) inter-rater reliability
2) test-retest reliability
Explain inter-rater reliability
Agreement of diagnosis between assessors.
The DSM-III was published in 1980; a reliable classification system for greater agreement of SZ diagnosis between psychiatrists.
Explain test-retest reliability
Whether tests to measure SZ are consistent over time.
Who tested the test-retest reliability?
Wilks et al (2003)
What did wilks et al (2003) do/find studying test-retest reliability?
Administered two forms of cognitive screening tests to SZ patients over intervals varying between 1-134 days.
Test-retest reliability correlation was high at .84.
What does validity refer to in SZ diagnosis?
The extent that a diagnosis represents something real and distinct from other disorders and extent to which classification systems measure what they claim to measure.
What is comorbidity?
Refers to extent that two or more conditions co-occur. Psychiatric comorbidities are common in SZ patients.
What comorbidities commonly occur alongside SZ?
Substance abuse
Anxiety
Depression
Who studied comorbidity in SZ patients?
Buckley et al (2009)
What did Buckley et al (2009) estimate about comorbidity in SZ patients?
Comorbid depression occurs in 50% patients.
Comorbidity of substance abuse occurs in 47% patients.
What difficulties does comorbidity in SZ patients arise?
Difficulty in the diagnosis of disorder and deciding what treatment to advise.
Who studied the validity of positive/negative symptoms for SZ diagnosis?
Klosterkotter et al (1994)
What did Klosterkotter et al (1994) find about the validity of positive/negative symptoms for SZ diagnosis?
(Who did they assess?)
Assessed 489 admissions to psychiatric unit in Germany.
Found that positive symptoms were more useful for diagnosis.
Define prognosis
Medical term for predicting a likely outcome.
Why is prognosis difficult with SZ patients?
SZ patients rarely share the same symptoms or outcomes.
Who studied prognosis for SZ patients?
What statistics did they find about SZ outcomes?
Bentall et al (1998)
20% recover to previous level of functioning
10% achieving significant improvement
30% showed improvement with relapse
What does difficulty with prognosis mean for issues of validity?
Diagnosis of SZ has little predictive validity.
Evaluation: ☹️
Who found that the inter-rater reliability correlations for DSM-lll were as low as .11?
Whaley (2001)
Evaluation: ☹️
What is the only characteristic symptom needed for SZ diagnosis?
Why is this a problem for reliability?
‘If delusions are bizarre’
This definition is not specific; v subjective.
Evaluation: ☹️
Who studied unreliable symptoms for diagnosis reliability?
Mojtabi and Nicholson (1995)
Evaluation: ☹️
What did Mojtabi and Nicholson (2003) do/find studying unreliable symptoms in the US?
Asked 50 senior psychiatrists to differentiate between ‘bizarre’ and ‘non-bizarre’ delusions.
Produced inter-rater reliability correlations of only +.40.
Evaluation: 😊
Who analysed test-retest reliability by studying several measures of attention and info processing?
Who did they study and what were the results?
Prescott et al (1986)
Studied 14 chronic SZ patients.
Found test-retest reliability stable over 6 month period.
Evaluation: ☹️
Who conducted the experiment ‘On Being Sane in Insane Places’?
Rosenhan (1973)
Evaluation: ☹️
Explain Rosenhan’s study (low reliability of diagnosis)
Normal people presented themselves to US psychiatric hospitals claiming they heard unfamiliar voices saying the words ‘empty’, ‘hollow’ and ‘thud’. They were all diagnosed with SZ and admitted. Throughout their stay, none of the staff recognised that they were pseudo patients.
Evaluation: ☹️
Describe Rosenhan’s follow up study
Rosenhan warned hospitals of his intentions to send out more ‘pseudo patients’.
This resulted in a 21% detection rate- even though he never sent any!
Evaluation: 😊
Comorbidity: what comorbid condition increases the risk for suicide?
Depression
Evaluation: 😊
Comorbidity: who studied comorbid suicide rates? What did they find?
Kessler et al (1994)
Rate for attempted suicide rose from 1% for those with SZ alone to 40% with at least one comorbid mood disorder.
Evaluation: ☹️
Symptoms: why might the identification of symptoms not always make SZ diagnosis highly valid?
The symptoms are also found in many other disorders, such as bipolar disorder and depression.
Evaluation: ☹️
Who pointed out that people with dissociative identity disorder (DID) actually have more schizophrenic symptoms than people diagnosed with SZ?
Ellason and Ross (1995)
Evaluation: ☹️
Who studied cultural differences in diagnosis?
(Reliability)
Copland (1971)
Evaluation: ☹️
What did Copeland (1971) do/find studying cultural differences in diagnosis?
Gave 134 US and 194 British psychiatrists a description of a patient.
69% of US psychiatrists diagnosed SZ but only 2% of British psychiatrists gave same diagnosis.
