diagnosis and classification of schizophrenia

• what is the DSM?

  a manual on mental disorders
• what is the ICD-11?

  an international system used to classify all illnesses and diseases, made by the World Health Organisation
• what 5 types of schizophrenia did the DSM-5 have?

  1. paranoid
  2. catatonic
  3. disorganised
  4. undifferentiated
  5. residual
• what two extra types of schizophrenia did the ICD 10 have?

  1. post schizophrenic
  2. simple
• what is criterion A?

  1. delusions
  2. hallucinations
  3. disorganised speech
  4. grossly disorganised or catatonic behaviour
  5. flattening - negative symptoms
  6. obvious problems in social functioning
• what does the DSM require for someone to be diagnosed with schizophrenia?

  two or more of the criterion A symptoms, each present for at least a month
• what was the old requirement for schiz diagnosis in the DSM5?

  only one critereon A symptom, if the delusions were judged to be "bizarre", or if the hallucinations consist of hearing one voice participating in running commentary with the patients actions. Or, if the patient heard two or more voices conversing with each other
• to be diagnosed using the DSM5, what is also needed?

  poor social functioning for a significant portion of the time since the onset
• the DSM5 used a multi axial assessment system. in this, they would test other possible causes of the symptoms and rule them out until they're sure its caused by schizophrenia, making it more accurate
• what changes happened to the DSM5?

  • removed the one symptom criteeria. now you need to have two and one has to be from the first three [positive symtpoms: hallucinations, delusions or disorganised speech]
  • APA made the change to the diagnositic criteria as it believes this improves reliability
  • APA abandoned 5 schizophrenic subtypes due to low reliability and validity
  • now use a schizophrenic spectrum
• how does the DSM 5 diagnose schizophrenia?

  1. two or more of critereon A for at least a month, one must be either delusions, hallucinations or disorganised speech
  2. must be impairment in one major area of functioning for a significant period of time [e.g. work, interpersonal, self care]
  3. disorder must last for a continuous period of at least 6 months, including one month of symptoms in critereon A
  4. schizoaffective and bipolar or depressive disorder has been ruled out
  5. disturbance not caused by substance / medical condition
  6. no history of autism unless prominant delusions
• what is the Clinician - Rated dimensions of psychosis symptom severity?

  allows for patients to be diagnosed and assessed more as individuals, and their treatment is more tailored to their symptoms. this increased both reliability and validity of diagnosis
• inter rater reliability 


  the extent to which psychologists agree on a diagnosis
• validity - concurrent validity

  do different classification systems arrive at the same diagnosis for the same patient and can it be diagnosed as a unique condition with characteristics, signs and symptoms
• symptom overlap


  where symptoms of schizophrenia are also symptoms of other conditions [bipolar disorder]
• comorbidity 


  where two conditions co - exist in the same individual at the same time and have a tendency to co - exist alongside each other
• Buckley 


  50 % of schiz patients suffer with substance abuse

  29 % of schiz patients suffer with PTSD

  23 % of schiz patients suffer with OCD

  this shows that schizophrenia commonly occurs alongside other mental illnesses and the disorders are co-morbid
• an example of symptom overlap

  lack of interest of pleasure and being easily distracted are symptoms of depression, bipolar disorder, and schizophrenia. the validity of diagnosis therefore may be reduced due to symptom overlap because individuals may not show all symptoms for a disorder so differentiation may be difficult.
• how comorbidityy impacts validity of diagnosis

  there may be symptom overlap between two comorbid conditions so thyey may only actually have one of the diagnosed conditions with other syptoms that are not part of the classification. it can also be hard to prescribe medication if two conditions are comorbid.