A03 Diagnosis And Classification Of Schizophrenia

• Poor reliability

  Cheniaux et al had two psychiatrists independently diagnose 100 people using DSM-5 and ICD-10. Inter-rater reliability was poor. The first psychiatrist diagnosed 26 with DSM-5 and 44 with ICD-10 with Schizophrenia. Whereas the second diagnosed 13 with DSM-5 and 24 with ICD-10.
• Poor validity


  Criterion validity assesses whether assessment systems arrive at the same diagnosis for the same person. The Cheniaux study shows schizphrenia is much more likely to be diagnosed using ICD-10 than DSM-5 which suggests that schizophrenia is over-diagnosed in ICD-10 or under-diagnosed in DSM-5.
• Co-morbidity


  Schiz is commonly diagnosed with other conditions. Buckley et al concluded that half of the people diagnosed with schiz also have a diagnosis of depression (50%) or susbstance abuse (47%). PTSD (29%) and OCD (23%) also present. This poses a challenge to the classificaiton to schiz (as depression and schiz may be the same) and diagnosis (as there is a causation issue)
• Symptom overlap


  Overlap between symptoms of schiz and other conditions like bipolar disorder. Both included positive symptoms of delusions, hallucinations and negative symptoms of avolition. Challenges classification and diagnosis of schiz. Under ICD-10 patient probably diagnosed with schiz but under DSM-5, same patient diagnosed with bipolar.
• Gender bias


  Longenecker et al reviewed studies of schiz. Concluded that since 1980s, men have been diagnosed with schiz more than women. Perhaps, man are more generically vulnerable. Alternatively, there may be gender bias as women 'typically' function better than men, are more likely to work and have good relationships. Their interpersonal functioning leads to under-diagnosis of schiz.
• Culture bias


  African Americans and English people of Afro-Carribbean origin are more likely to be diagnosed with schiz. There is culture bias as in such culturees, hearing voices is more acceptable and acknowledged. Escobar points out white psychiatrists tend to over-interpret symptoms and distrust the honesty of Afro-Carribbeans during diagnosis.