Validity of DSM

• Refers to the accuracy and objectivity of the info gathered

• Different disorders have different symptoms, these symptoms should not overlap. 

• Esyenck found 2/3rds of patients with anxiety disorder had one or more additional anxiety disorders

If some people have a few different disorders because they have similar symptoms then it may question VALIDITY of diagnosis.....are they really different or should they only be one disorder?

• Specific treatments are made for different diagnosis'

• If diagnosis = valid, treatment should work

• Heather (1976) pointed out:

only 50% chance of predicting which treatments will be given from diagnosis

Howerver, some cases there is predictive validity:

• Schizphrenic patients = improve when given neuroleptic drugs, other patients don't (specific)

•  Syndromes have specific causes
• Expect all those with the same disorder to have developed condition for the same reason
• NOT TRUE- many different reasons for disorders

E.g; Schizophrenia can have genetic basis in some cases but not in others

• Suggests the dianostic system is inadequate- can't all have the same causes

• Extent to which diagnoses agree from 2 different systems (DSM and ICD)
• Patient would be diagnosed the same in all the books

Andrews et al. (1999) 

• assessed 1500 people using DSM-IV and ICD-10 
• Found 68% agreement when diagnosing depression