Diagnosis and classification of schizophrenia

• Schizophrenia does not have a single defining characteristic. Made up of a cluster of symptoms which may appear unrelated. 
• World Health organisation's international classification of disease edition 10 (ICD-10)  

  • 2 or more negative symptoms must be present for a diagnosis  
• American Psychiatric Association Diagnostic and Statistical Maula edition 5 (DSM-5)  

  • 1 positive symptom must be present for diagnosis 
• Positive symptoms 


   Describes something extra/ an addition to somones life beyond normal experiences

  1. Hallucination
  2. Delusions
• Negative symptoms

  A reduction or loss of normal function 

  1. Avolition
  2. Speech poverty  
• Hallucinations

  • Sensory stimuli that have either no basis in reality or are distorted perceptions of things that are there  
  • Some hallucinations are related to events in the environments whilst others have no relationship to environment   
  • They can be related to any senses  

  e.g. - May see distorted facial expressions to people and animals that are not there 
• Delusions

  • Also known as paranoia, delusions are irrational beliefs that also have no basis in reality
  • These delusions may make a person behave in in ways that make sense to them but seem usual to others
  • Common delusions involve being Jesus, political or religious figures 
  • May involve being persecuted by governments or aliens  
• Avolition

  A difficulty to keep up with or begin goal oriented tasks  

  • Reduction in interests due to a lack of motivation/ energy  

  Andreason 1982 et al -  

  • Identified three signs of avolition  

  1. Poor hygiene and grooming  
  2. Lack of persistence in school or work  
  3. Lack of energy  
• Speech poverty

  • Reduced frequency and quality of speech  

  ICD- 10 - recognises this as a negative symptom  

  DSM-5 - focuses more on speech disorganisation - where speech become incoherent.  
• Reliability - 🙁  

  • Thinking about consistency between diagnosis  
  • Inter-rater reliability – Extent to which two or more mental health professionals arrive at the same    
  • Elie Cheniaux et al. (2008) - had two psychiatrics independently diagnose 100 people using DSM and 1CD criteria  
  • Inter-rater reliability was poor  
  • One psychiatrist diagnosing 26 with schizophrenia according to DSM and 44 according to ICD  
  • The other diagnosing 13 using DSM and 24 according to ICD  
• Validity - 🙁  

  • Describes the extent to which we are measuring what we are intending to measure  
  • One standard way of assessing validity of a schizophrenia diagnosis is criterion validity  
  • Which looks at how different Sysmon's arrive at the same diagnosis for the same person  
  • Considering Cheniaux et al. (2008) results above we can see that schizophrenia is more likely to be diagnosed using ICD compared to DSM  
  • This suggests that schizophrenia is either over-diagnosed in ICD or under-diagnosed in DSM  
  • Poor validity and a weakness of diagnosis for schizophrenia 
• Co-morbidity - 🙁  

  • Co-morbidity refers is the phenomena that two or more contains occur together  
  • When conditions are diagnosed together it calls into questions the validity of the diagnosis as there may actually be only be a single condition 
  • Schizophrenia is most commonly diagnosed with depression  
  • Peter Buckley (2009) -concluded that around half the people with a schizophrenia diagnosis also have diagnosed depression (50%) and substance abuse (47%)  
  • PTSD also occurs in 29% of cases and OCD in 23%  
  • This challenged both the classification and diagnosis process of schizophrenia 
• How does co-morbidity challenge the diagnosis of schizophrenia?

  • Because there such a high correlation between depression and schizophrenia diagnosis are psychiatrists just bad at telling the two conditions apart  
• How does co-morbidity challenge the classification of schizophrenia?

  • It may be that sever schizophrenia looks like depression and vice versa - this may be that it's better to see them as just one condition 
• Overall co-morbidity..

  paints a confusing picture and is a large weakness of diagnosis and classification of schizophrenia 
• Symptoms overlap - 🙁  

  • There is a considerable overlap between the symptoms of schizophrenia and other conditions  
  • Both schizophrenia and bipolar involve positive symptoms like delusions and negative symptoms like avolition 
  • Calls into question the validity of both the classification and diagnose of schizophrenia 
  • Under ICD a person might be diagnosed with schizophrenia, but those same individuals may receive a diagnosis of bipolar according to DSM criteria  
  • May even suggest the bipolar and schizophrenia are just a single condition 
• Gender bias on diagnosis - 🙁  

  • Longenecker et al (2010) - reviewed studies for the prevalence of schizophrenia. Found that men since the 1980s more likely to be diagnosed with schizophrenia than women.  
  • Prior to 1980s there had been no difference in the diagnosis between the genders   
  • Cotton et al (2009) - found that women compared to men function better.  
  • It’s this high functioning which may explain why women are underdiagnosed when men with similar symptoms are diagnosed  
  • May lead to bias with the psychological practitioner and cause them to underdiagnose female patients 
• Cultural buas in diagnosis - 🙁   

  • African Americans and Afro- Caribbeans have a high chance of being diagnosed
  • Positive symptoms of schizophrenia like hearing people talk is more common in those cultures  
  • Unique culture voices are seen as their ancestors and communication with them is encouraged  
  • When it's recoded to psychiatrist from a different culture these experiences may be seen a bizarre therefore leading to a diagnosis
  • Escobar (2012) has pointed out that white psychiatrists tend to over interpret their symptoms and distrust the honesty of Afro-Caribbeans during diagnosis.  
• Co-morbidity, gender and cultural bias and symptom overlap ALL impact the validity of a diagnosis of schizophrenia. Questions if these classification systems measure what they intend to measure
• Further research into issues of reliability - 🙁  

  P - Further supporting the idea that there are significant issues with the classification symptoms is Rosenhan’s study. - 1973

  E - His study ‘Being sane in insane places’, all 8 ‘patient’s were diagnosed with mental health issues and admitted to the psychiatric wards, despite them faking their initial symptoms.

  A - Highlighted the unreliability of the diagnostic systems being used at the time
• CP to issues surrounding reliability

  P - HW, this study did take place over 40 years ago and diagnostic manuals have since been updated.

  E - For example, categories and definitions are more detailed and operationalised and psychiatrists now use standardised interview schedules when assessing patients.

  A - Also the ICD and DSM have been bought in line with one another so they are now very similar, so many of the studies discussed may now be outdated