Classification & Diagnosis

• Diagnosis and Classification

  Affects 1%, commonly diagnosed in men, working-class and in cities
• ICD-10 (International Classification of Disease edition 10)

  Diagnosed when have 2+ negative symptoms
• DSM-5 (Diagnostic and Statistical Manual edition 5)

  Diagnosed when have positive symptoms
• Positive symptoms

  Additional experiences - features you gain from the condition
• Positive symptoms

  • Speech poverty under DSM-5
  • Hallucination
  • Delusions
• Hallucinations

  Unusual sensory experiences
• Delusions

  Irrational beliefs that can affect the body by making you behave in ways that only make sense to you
• Negative symptoms

  The loss of abilities and experiences
• Negative symptoms

  • Avolition
  • Speech therapy under ICD-10
• Avolition

  The loss of motivation to carry out tasks and cause lower energy levels
• Avolition research - Andreason 1982 et al. found signs = poor hygiene, lack of persistence in work or education
• Speech poverty

  The reduced frequency and quality of speech
• Limitation - low reliability


  Cheniaux 2009 = two psychiatrists independently diagnose 100 people: one psychiatrist diagnose 26 (DSM) and 44 (ICD), the other diagnose 13 (DSM) and 24 (ICD) - inter-rater reliability was poor therefore diagnoses aren't reliable
• Limitation - low validity


  Cheniaux 2009 et al = both psychiatrists diagnosed more under ICD - schizophrenia is more likely diagnosed under ICD therefore different assessment systems don't arrive at same diagnosis for same person and schizophrenia is either over-diagnosed in ICD/under-diagnosed in DSM
• Limitation - confusing classification and diagnosis

  • Buckley 2009 = 50% of schizophrenics have depression diagnosis and 47% have substance abuse diagnosis; 29% have PTSD and 23% have OCD - difficulty telling difference between conditions therefore co-morbidity increases confusion
• Co-morbidity

  two or more conditions occur together
• Limitation - symptom overlap


  Schizophrenia and bipolar disorder both have delusions and avolition - schizophrenia may be diagnosed under ICD but bipolar disorder may be diagnosed under DSM therefore they may not be two different disorders
• Limitation - gender bias diagnosis

  • Longenecker 2010 = men more often than women diagnosed with schizophrenia since 1980s; Cotton 2009 = women have good family relationships and function better - women under-diagnosed because their interpersonal functioning biases practitioners therefore low internal validity