Issues of diagnosing and classifying schizophrenia

• There are 2 manuals used to diagnose schizophrenia.

  One being the DSM-V and the other is the ICD-11.
• The DSM-V states you must have one positive symptom of schizophrenia in order to make a diagnosis e.g. hallucinations.

  The ICD-11 states you must have two negative symptoms of schizophrenia in order to make a diagnosis e.g. speech poverty and avolition.
• The issues with this is that they do not have continuity in diagnostic criteria which results in subjective interpretation and thus differing interpretation within the 2 manuals.

  This presents issues of reliability resulting in low inter-rater reliability.
• Research support for poor inter-rater reliability comes from Cheniaux et al who found that one psychiatrist diagnosed 26 of 100 potential patients with schizophrenia using the DSM-V and another psychiatrist diagnosed 44 of 100 using the ICD-11.

  This shows how the different diagnostic criteria lead to differing diagnosis and how that affects the inter-rater reliability.

  Furthering this is Walley who found a correlation coefficient of 0.11 when using the DSM-V (extremely poor inter-rater reliability) which calls into question the validity of the diagnosis.
• Also symptoms of schizophrenia may be the same as organic and other psychological disorders.

  For example hallucinations and avolition have been found in BPD sufferers, depression and prolonged substance abuse.

  This can lead to one psychiatrist diagnosing schizophrenia and another diagnosing BPD.

  Evidence from Ellason and Ross suggested that patients with DID showed more symptoms of Sz than actual schizophrenic patients.

  If the diagnosis is not consistent and thus reliable then perhaps it's not valid as it may be the result of misdiagnosis.
• Co-morbidity is the presence of two or more disorders at the same time and it can also lead to issues of diagnosis.

  For example Buckley found that 47 % of Schizophrenics also suffered with substance abuse and 50 % suffered with depression.

  This results in issues because you can't be sure if the symptoms presented are the result of one severe condition or 2 separate conditions occurring simultaneously.

  This can lead to issues of misdiagnosis and this is turn could lead to faulty treatment plans which could lead to more damage.
• In the UK, people of afro-carribbean descent are 10 x more likely to be diagnosed with schizophrenia, not because of genetic vulnerability but due to bias in diagnosis.

  In the UK, hallucinations are deemed to be a manifestation of mental illness specifically Sz, but in afro-carribbean cultures they are seen to be a sign of communication with ancestors.

  Because of this there is an increased diagnosis and overdiagnosis of people of afro-carribbean descent and an underdiagnosis of people from other cultures.
• There is also gender bias within diagnosis as men are more likely to be diagnosed with schizophrenia than women.

  1 woman for every 1.4 men is diagnosed with Sz.

  This can lead to the underdiagnosing of women or perhaps the misdiagnosis of women as women are often diagnosed with bipolar.

  This then leads to women not being treated appropriately for their disorder.