AO3: Schizophrenia Classification

• Inter-rater reliability


  The extent to which psychiatrists can agree on the same diagnosis when independently assessing patients
• Validity


  The extent to which we are measuring what we are intending to measure
• Concurrent validity


  Whether different assessment systems arrive at the same diagnosis for the same patient
• Rosenhan (1973) study


  • Healthy 'pseudopatients' could gain admission to psychiatric hospital by pretending to have auditory hallucinations
  • Staff interpreted the behaviours of the pseudopatients, who were now behaving normally, as symptoms of their disorder
• Although systems of classification and diagnosis have changed considerably since the 1970s, many people still have concerns about their accuracy and appropriateness
• Cheniaux et al (2009) study found poor inter-rater reliability between psychiatrists using DSM and ICD criteria to diagnose schizophrenia
• The classification systems may not be reliable due to poor inter-rater reliability, and may not be valid due to differences in diagnoses when using different classification systems
• Co-morbidity


  The occurrence of at least one other condition alongside schizophrenia
• Buckley et al. (2009) found that around half of patients with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%), and 29% have post-traumatic stress and 23% have OCD
• There is a lot of overlap between the symptoms of schizophrenia and other conditions, such as bipolar disorder, which calls into question the validity of the classification and diagnosis of schizophrenia
• Misdiagnosis due to symptom overlap can lead to years of delay in receiving relevant treatment, during which time suffering and further degeneration can occur, as well as high levels of suicide
• Harrison et al. (1984) and Cochrane (1977) studies


  • People of West Indian/Afro-Caribbean origin were over-diagnosed with schizophrenia by white doctors
• The cause of cultural bias in diagnosis may be that positive symptoms like hallucinations are more acceptable in some cultures, and psychiatrists from different cultures may misinterpret these experiences as symptoms of schizophrenia
• Since the 1980s, men have been diagnosed with schizophrenia more often than women, which may be because females with schizophrenia have been found to function better than men, leading to under-diagnosis in females
• Loring and Powell (1988) study found that psychiatrists were more likely to diagnose schizophrenia in patients described as male compared to those described as female
• Gender bias in diagnosis may also occur due to clinicians failing to consider differences in symptoms and risk factors between males and females