evaluation sz

• One way of measuring how consistent and reliable diagnosis is through testing inter-rate reliability. This involves two assessors independently arriving to the same conclusion. 
• Powell (1988) randomly selected 290 male and female psychiatrists to read two case vignettes of patients behaviour and give their diagnosis using the standard diagnostic criteria. When the patients were described either as “males” or their gender was not specified, 56% of psychiatrists gave a diagnosis of schizophrenia. When patients were described as “female” only 20% were diagnosed as having schizophrenia highlighting support for how much of a factor gender bias is in unreliable diagnosis.
•  Also the interpretation of symptoms is subjective and down to the person doing the diagnosis so a great deal of importance is placed on the individual’s ability in diagnosis which may vary between health professionals. Therefore skill, experience and knowledge further affect reliability and diagnosis.
• Peter Buckley (2009) found up to 50% of patients diagnosed with schizophrenia also fit into the diagnosis for depression and 29% suffered from post-traumatic stress disorder and OCD (23%). This poses a challenge for the validity of schizophrenia as a disorder itself because if we are unable to distinguish it from other disorders, the reliability of diagnosis by clinicians will also be inconsistent.
• Fernando (1988) argued that people from ethnic minorities experience greater levels of racism, prejudice, poverty than the white population and these stressors trigger schizophrenia and explained cultural biases so should be expected in diagnosis.
• However Cochrane (1983) highlighted how it was only the afro-caribbean people who were more likely to be diagnosed and one possible explanation proposes the diagnosis of the disorder is valid but people of this background have little immunity to the flu (an illness common in Britain but not their country of origin). Children born to mothers who had the flu while pregnant have an 88% increased chance of developing schizophrenia which would explain higher levels of diagnosis in afro-caribbean people.
• : If a diagnosis is inconsistent, it has serious consequences for treatment. Patients may be wrongly diagnosed with schizophrenia and given powerful antipsychotic drugs, exposing them to unnecessary side effects, while those who actually have schizophrenia may go undiagnosed and untreated, leading to worsening symptoms and higher relapse rates. The lack of diagnostic reliability also complicates research into schizophrenia, as studies may be based on inaccurate patient classifications, reducing the validity of findings.