Schizophrenia - issues with classification&diagnosis; reliability&validity

Question 1

Cooper - reliability

Answer 1

• American and British psychologists
• shown same videotaped interviews and asked to make diagnosis
• American psychologists diagnosed schizophrenia twice as often, British psychologists diagnosed mania and depression twice as often

Question 2

Cheniaux - reliability

Answer 2

• rates of diagnosis for schizophrenia were significantly higher for ICD than DSM-IV

Question 3

Motjabi and Nicholson - reliability

Answer 3

• weak inter-rater reliability between clinicians in judgement of whether hallucinations were ‘bizarre’ or not

Question 4

Beck - improvements to reliability

Answer 4

• two doctors diagnosed 154 patients

- inter-rater reliability was as low as 54%

Question 5

Cheniaux - improvements to reliability

Answer 5

• found kappa statistic of 0.59 for DSM-IV

Question 6

Rosenhan

Answer 6

• actors reported they were hearing voice saying ‘thud’

- all but one received diagnosis of schizophrenia

Question 7

Schwartz - consequences for lack of validity

Answer 7

• woman was treated as schizophrenic as she had hallucinations
• EEG revealed she had epilepsy and when she had proper treatment her symptoms disappeared
• anti psychotics alleviated some of her symptoms, leading to false confirmation of her illness

Question 8

Perlman - consequences for lack of validity

Answer 8

• patients were diagnosed with schizophrenia as they showed negative symptoms
• administered unnecessary anti psychotics which attempted to remove characteristics of Asperger syndrome