Classification of Schizophrenia

• What is classification?


  Classification is the process of organising symptoms into categories.
• What is diagnosis?


  Diagnosis is when you identify a mental illness such as schizophrenia using symptoms from the classification list.
• What is DSM?

  The DSM is the most widely used diagnostic tool across America -in order to be diagnosed with schizophrenia under the DSM, the patient must have 1 severe positive symptom for at least 6 months.
• What is ICD?


  The ICD was produced by the world health organisation - in order to be diagnosed with schizophrenia under the ICD you need two or more negative symptoms for at least 6 months.
• Schizophrenia symptoms are divided into two catergories: Positive and Negative symptoms.
• Positive symptoms are atypical symptoms in addition to normal experiences.
• Positive symptoms include delusions, hallucinations, disorganised speech and grossly disorganised or catatonic behaviour
• Negative symptoms are atypical experiences that represent the loss of unusual experiences such as the loss of clear thinking or loss of motivation.
• The positive symptom of hallucinations refers to an unusual sensory experience that either has no relation or basis in reality or are distorted perceptions of reality.
• The positive symptom of delusions are beliefs that have no basis in reality, for example believing that they are a victim of a conspiracy theory.
• There are two main negative symptoms: speech poverty and avolition.
• The negative symptom speech poverty is the reduction of frequency and quality of speech in a patient.
• Disorganised speech is where the patient's speech is difficult to understand because it may contain irrelevant information, tangents, neologisms (made up words) and word salad.
• The negative symptom avolition is the loss of motivation to carry out tasks such as not showering resulting in poor hygiene.
• Reliability of the diagnosis and classification of schizophrenia. 


  • For a diagnosis to be reliable it must show consistency and agreement across diagnosing clinicians.
• Reliability of the diagnosis and classification of schizophrenia. 


  • Inter-rater reliability refers to when more than one clinician is diagnosing the same patient with schizophrenia - all clinicians agree on the same diagnosis for the same patient.
  • Copeland (1971) conducted study where 134 USA and UK psychiatrists were given a description of patients and found that 67% of USA psychiatrists diagnosed them with schizophrenia compared to only 2% of UK psychiatrists.
• Validity of the diagnosis and classification of schizophrenia.


  • Elie Cheniaux et al (2009) asked two psychiatrists to independently asses the same patients, once using the ICD-10 system and the other time using the DSM-IV system.
  • They found that 68 people were diagnosed with schizophrenia under the ICD-10 system whilst only 39 people under the DSM-IV.
  • This discrepancy with the findings highlights a low validity within the diagnosis and classification of schizophrenia.
• Evaluation of the diagnosis and classification of schizophrenia.


  • Co-morbidity refers to the occurrence of two disorders/conditions together such as hallucination being a symptom for both depression and hallucinations.
  • When to conditions such as depression and schizophrenia are so frequently diagnosed together, it calls into question the validity of the classification of the two disorders as separate conditions.
• Evaluation of the diagnosis and classification of schizophrenia. 


  • One limitation is cultural bias.
  • Hearing voices is a symptom of schizophrenia however, in some cultures it is a way to connect with your ancestors and is seen as normal social practice.
  • Pinto and Jones 2008 found that British African Caribbean people are up to 9 times more likely to be diagnosed with schizophrenia due to the over interpretation of their symptoms.
• Evaluation of diagnosing and classifying schizophrenia


  • One issue with schizophrenia is that there are two systems used for classification of schizophrenia.
  • Whilst the DSM and ICD both have similar criteria there are very distinct differences such as the period of time symptoms are present for and which symptoms are present.
  • In additon, there are multiple other ways of classification such as Type 1 and Type 2 schizophrenia and the Schneider system.
• Evaluation of diagnosing and classifying schizophrenia.


  • There is no single symptom that is only found in schizophrenia and not in any other mental disorder - symptom overlap.
  • Psychosis is both a symptom of bipolar disorder and schizophrenia, hence do you have schizophrenia or bipolar disorder.
• What is the focus of the evaluation discussed in the study material?

  Diagnosis and classification of schizophrenia
• What limitation of schizophrenia is highlighted in the study material?

  Gender bias
• Who conducted the study on gender bias in schizophrenia diagnosis?

  Loring and Powell
• How many psychiatrists participated in the study conducted by Loring and Powell?

  290 psychiatrists
• What were the psychiatrists asked to do in the study?

  Read articles and diagnose patients with or without schizophrenia
• What percentage of male patients were diagnosed with schizophrenia in the study?

  56%
• What percentage of female patients were diagnosed with schizophrenia in the study?

  20%
• How did the gender bias manifest in the study regarding the psychiatrists' diagnoses?

  Male patients were diagnosed more frequently than female patients
• Did the gender bias occur when female psychiatrists diagnosed patients?

  No, the bias did not occur with female doctors
• What are the key findings of Loring and Powell's study on gender bias in schizophrenia diagnosis?

  • Male patients diagnosed: 56%
  • Female patients diagnosed: 20%
  • Gender bias present among male psychiatrists
  • No bias observed with female psychiatrists
• Evaluation of the diagnosis and classification of schizophrenia.


  • Rosenhan (1973) sent 8 pseudopatients to mental hospitals in the USA - each patient was told to act as if they were hearing voices during their appointment, but once admitted they were told to act normal.
  • The pseudopatients were kept in the hospital from between 7-52 days.
  • This study inspired the efforts to form a systematic way of diagnosing mental illnesses.