Reliability and Validity

Reliability in diagnosis and Classification of Schizophrenia: 

• Reliabilty refers to the consistency of classfication system such as DSM 
• The diagnosis of schizophrenia must be repeatable
  • Test-retest
    • clinicians must be able to reach the same conclusions at two different times 
  • Inter-rater reliability 
    • Different clinicians must be able to reach the same conlusions at the same time 
    • This can be measured using the kappa score 
      • <0.7 indicates lack of agreement, same conclusions not reached
      • 1 indicates perfect inter-rater reliability 
      • >0.7 is considered as a good inter-rater reliablity 
      • 0 indicates zero agreement 

Cultural differences in diagnosis: 

• Copeland(1971):
  • 134 US and 194 Bristish psychiatriats given a desciption of a patient and asked to diagnose this patient 
  • 69% US psychiatrists gave the diagnosis of schizophrenia 
  • 2%of British gave similar diagnosis
• Study shows that there are cultural differences between the diagnosis 
• Luhrmann(2015):
  • Interviewed 60 adults who had been diagnosed with schizophrenia 
  • 20 each from Ghana, India and US
  • Each had been asked about the voices they had been hearing and their experiences with these voices 
  • Many African and Indian subjects reported having positive experiences with the voices as opposed to the US…