Classification system Flashcards
What are the names of the two diagnostic systems used for Schizophrenia?
DSM-IV (UK+US) and ICD (Europe)
What positive symptoms come under the diagnostic criteria?
Delusions.
Experiences of control (under the control of a something that may have invaded them).
Bizarre hallucinations.
Disordered thinking.
What negative symptoms come under the diagnostic criteria?
Affective flattening (reduction of emotional intensity).
Alogia (lesser speech fluency and productivity).
Avolition (reduction or inability of motivation.
Describe the issues of reliability (diagnosis in general) with the diagnostic system.
Reliability is the extent to which psychiatrists can agree on the same diagnoses.
Carson claimed that it had fixed reliability once and for all by leading to much greater agreement on the diagnosis.
HOWEVER
Still little evidence that DSM is routinely used with high reliability by clinicians.
Whaley found inter-rater reliability to be 0.11
Describe the issues of reliability (symptoms) with the diagnostic system.
Klosterkotter assessed 489 admissions. Positive symptoms are more useful for diagnosis.
It’s criticized that the diagnosis of schizophrenia is too diffuse to be useful (can give two people with completely different behaviours same diagnosis)
Mojtabi found 0.40 interrater reliability on the definition of ‘bizarre’ hallucinations.
Lacks sufficient reliability to be a reliable method of distinguishing schizophrenia.
Describe the issues of validity (symptoms) with the diagnostic system.
Validity is meaningless without reliability.
Schneider created category ‘first rank symptoms’ that are distinguishable from other disorders (delusions of control by an external force, voices that comment on actions).
Meant to make reliability more achievable, but some symptoms are found in other disorders.
Ross found that people with dissociative identity disorder have more schizophrenic symptoms than schizophrenics.
Describe the issues of validity (prognosis) with the diagnostic system.
No evidence that those with same schizophrenia share same outcomes.
20% recover to functioning level
10% achieving significant and lasting improvement
30% showing some improvement with intermittent relapses.
Has little predictive reliability.
Describe the influence on the outcomes of Schizophrenia.
Malmberg found that gender and psychosocial factors (academic achievement, social skills) have more of an influence on the outcome. Supported by Harrison.
Describe the cultural differences in the reliability of diagnosis.
Copeland gave a description of a patient to US and UK psychiatrists. 69% of US clinicians diagnosed schizophrenia, while only 2% UK clinicians did.
Shows that there is a massive difference between countries on the standard of symptoms.
List the diagnostic criteria for schizophrenia.
A. Characteristic symptoms.
B. Social/occupational dysfunction.
C. Duration (lasts 6months+).
D. Exclusion of mood disorders (no major episodes).
E. Exclusion of known organic causes (not due to drugs.
