diagnosis & classification

• how often does schizophrenia occur?

  1% of population
• key criteria for DSM-5

  • 1 or more positive symptoms
  • symptoms persist for at least 6 months with 1 month of active symptoms
  • cause significant impairment in work, relationships or self-care
• how is schizophrenia classified?

  • ICD-10
  • DSM-5
• what symptoms are under the criteria for the DSM-5?

  • delusions
  • hallucinations
  • disorganised speech
  • catatonic behaviour
  • negative symptoms
• define delusions

  false beliefs resistant to contrary evidence
• define positive symptom

  excess of usual functioning; an added behaviour or experience
• what are 2 main positive symptoms of schizophrenia?

  1. delusions
  2. hallucinations
• define hallucinations

  false sensory experiences

  • most commonly auditory
• define disorganised speech

  speech that is incoherent or difficult to follow
• define negative symptom

  loss of usual functioning
• what are the two main negative symptoms?

  1. avolition
  2. speech poverty
• define catatonic behaviour

  • unusual movements
  • extreme agitation
  • complete lack of movement
• what is the main focus of the DSM-5?

  dimensional approach

  • symptom severity
• what does reliability refer to?

  consistency of diagnosis
• what are the 2 types of reliability?

  1. inter-rater
  2. test-retest
• define inter-rater reliability

  different clinicians diagnose the same patient with the same condition
• outline what validity is

  extent to which classification of schizophrenia is a true reflection of the illness
• outline the study into inter-rater reliability

  Cheniaux et al

  • two psychiatrists diagnosed 100 patients
  • using DSM it diagnosed 26 with schizophrenia
  • using ICD it diagnosed 44 with schizophrenia
• define test-retest reliability

  diagnosis changes over time due to inconsistent classification and symptom severity
• what are the two issues impacting validity?

  1. co-morbidity
  2. symptom overlap
• define symptom overlap

  different diagnoses share the same symptoms
• outline the study into symptom overlap

  Ellasson & Ross

  • patients with dissociative identity disorder had more schizophrenic symptoms than actual schizophrenics
• define comorbidity

  presence of different disorders at the same time in the same patient
• outline the study into co-morbidity

  Buckley et al

  • 50% of schizophrenic patients also had depression
  • 47% had substance abuse
  • 23% had OCD
• what are the 2 types of bias?

  1. culture
  2. gender
• key criteria for the ICD-11

  • broader diagnosis as considers cognitive and mood symptoms
  • symptoms must persist for at least 1 month
• what are the 3 subtypes recognised by ICD-11?

  1. paranoid schizophrenia
  2. catatonic schizophrenia
  3. disorganised schizophrenia
• what are the 4 main positive symptoms?

  • delusions
  • hallucinations
  • disorganised speech
  • catatonic behaviour
• what are the 4 main negative symptoms?

  • avolition
  • speech poverty
  • anhedonia
  • flat affect
• define avolition

  lack of motivation or inability to initiate goal-directed activities
• define speech poverty

  limited speech output or difficulty forming thoughts
• define anhedonia

  loss of interest or pleasure in activities
• define cultural bias

  certain behaviours are normal in some cultures but not in others
• outline the study into cultural bias

  Escobar

  • white psychiatrists overdiagnose black patients
• outline the study into gender bias

  Cotton et al

  • women show better interpersonal functioning which leads to underdiagnosis
• explain the impact of reliability issues

  • inconsistent diagnosis
  • poor treatment
  • overdiagnosis or underdiagnosis
  • difficulties in research
  • ethical issues
• explain the impact of validity issues

  • misdiagnosis due to symptom overlap and co-morbidity
  • bias leads to overdiagnosis or underdiagnosis
  • problems with research and treatment