Schizophrenia evaluation

Weakness: inter-rater reliability in diagnosis is poor

• Elie Cheniaux et al (2009) had two psychiatrists independently diagnose 100 patients using both the DSM and ICD criteria
• Inter-rater reliability was poor, with one psychiatrist diagnosing 26 with schizophrenia according to the DSM and 44 according to the ICD, and the other diagnosing 13 according to the DSM and 24 according to the ICD

Weakness: there is low validity in diagnosis

• From the Cheniaux et al (2009) study, it is clear that schizophrenia is more likely to be diagnosed using the ICD than the DSM
• This suggests that schizophrenia is either over-diagnosed in ICD or under-diagnosed in DSM; either way, this is poor validity and is a weakness of diagnosis

Weakness: comorbidity

• If two conditions occur together a lot of the time, this calls into question…