Classification and Diagnosis

• Schizophrenia


  a severe mental disorder where contact with reality and insight are impaired.
• Classification of Sz

  The two main systems for the classification of a mental disorder are the ICD-10 and the DSM-5. These differ slightly in classifying schizophrenia, for example, the DSM-5 requires one positive symptom for the diagnosis, whereas two or more negative symptoms are sufficient for the ICD-10. Both manuals dropped any subtypes as they tended to be inconsistent.
• Positive symptoms of schizophrenia

  Positive symptoms add to a person's psyche. E.g. Hallucinations, unusual sensory experiences like hearing voices or seeing things that aren't there and Delusions, irrational beliefs like believing they are an important historical figure (Jesus or a king etc.) or that they are being hunted by police, government or aliens. A person may also believe they are under the control of something external. Delusions may make a person act in ways that seem bizarre to others.
• Negative symptoms of schizophrenia

  Negative symptoms take away from a person's psyche. E.g. speech poverty, reduced frequency and quality of speech and Avolition, loss of motivation to carry out tasks, resulting in lower activity levels.
• Diagnosis and Classification reliability

  A strength is that the diagnosis is said to have good reliability when clinicians reach the same diagnosis for the same individual (inter-rater reliability) and when the same clinician reaches the same diagnosis for the same individual on two occasions (test-retest reliability). Prior to the DSM-5 reliability for schizophrenia was low but has since improved. This means we can be reasonably sure that the diagnosis of schizophrenia is consistently applied.
• Validity of diagnosis limitation

  A limitation is the diagnosis has low validity. In comparing the use of the ICD-10 and the DSM-5 it was found that in a sample of 100 clients 68 were diagnosed when using the ICD and only 39 with the DSM, suggesting schizophrenia may be either very over or very underdiagnosed according to the diagnostic system. Giving it low criterion validity.
• Counterpoint to the limitation of diagnosis validity

  A Counterpoint is that Osorio et al found there was excellent agreement among clinicians when they used two measures to diagnose sz when both were derived from the DSM-5. Suggesting validity is very good providing it takes place within a single diagnostic system.
• Limitation of the diagnosis of Sz

  A limitation of diagnosis is SZ is commonly diagnosed with other conditions. For example, about half are also diagnosed with depression or substance abuse. This is an issue as it means SZ may not exist as a distinct condition, and is a problem for diagnosis as at least some people diagnosed with SZ may have unusual cases of conditions like depression.
• Gender bias in diagnosis

  A limitation of diagnosis is the existence of a gender bias. Men are more commonly diagnosed than women. One explanation is that women are less vulnerable than men, perhaps due to genetics. However it seems more likely that women are undiagnosed because they have closer relationships and hence get support. This leads women with schizophrenia to be better functioning than men.

   This underdiagnosing is a gender bias and means women therefore may not be receiving treatments and services that may benefit them.
• Cuture bias in diagnosis

  A further limitation is there is a culture bias in diagnosis. Symptoms like hearing voices have different meanings in different cultures. For example in Afro-Caribbean societies, voices may be attributed to communication from ancestors. Afro-Caribbean people living in the UK are up to 10x as likely to be diagnosed (there may also be a genetic vulnerability). This may be an overinterpretation of symptoms in black British people. This means Afro-Caribbean people may be discriminated against by culturally-biased diagnostic systems.
• A limitation of diagnosis

  A limitation of diagnosis is that there is considerable overlap with symptoms of other conditions. For example, SZ and BPD involve positive symptoms such as delusions and negative symptoms such as avolition. This suggests SZ and BPD may be variations of a single condition rather than separate, or hard to distinguish from each other. As with co-morbidity, it suggests Sz may not exist as a separate condition and even if it does it's hard to diagnose. So both classification and diagnose are flawed.