Introduction to Schizophrenia

• What is schizophrenia classified as?

  A severe mental disorder
• In which gender is schizophrenia more commonly diagnosed?

  Men
• How are diagnosis and classification interlinked in schizophrenia?

  • Distinguishing one disorder from another
  • Identifying symptoms to determine the disorder
• What are positive symptoms in schizophrenia?

  Atypical symptoms in addition to normal experiences
• What are hallucinations?

  Sensory experiences with no basis in reality
• How can hallucinations relate to the environment?

  Some are related, others are not
• What are delusions?

  Beliefs with no basis in reality
• What types of beliefs can delusions include?

  Beliefs about important figures or persecution
• What are negative symptoms in schizophrenia?

  • Atypical experiences representing loss of usual experiences
  • Examples include Speech Poverty and Avolition
• What is speech poverty?

  Reduced frequency and quality of speech
• What does speech poverty sometimes involve?

  A delay in verbal responses during conversation
• What is avolition?

  Loss of motivation to carry out tasks
• What can avolition result in?

  Lowered activity levels and poor hygiene
• What is reliability in psychiatric diagnosis?

  • Consistency in diagnosis
  • Measured by inter-rater and test-retest reliability
• What inter-rater reliability score did Osório et al (2019) report?

  +0.97
• What test-retest reliability score did Osório et al (2019) report?

  +0.92
• What does excellent agreement between clinicians indicate?

  Good criterion validity for diagnosis
• What did Cheniaux et al (2009) find regarding diagnoses?

  Discrepancies between ICD-10 and DSM-4
• What does co-morbidity in schizophrenia suggest?

  Conditions may be a single condition
• What other conditions are commonly diagnosed with schizophrenia?

  Depression and substance abuse
• What is gender bias in schizophrenia diagnosis?

  Men diagnosed more than women
• Why might women be underdiagnosed with schizophrenia?

  Better functioning due to support systems
• What does culture bias in diagnosis refer to?

  Different meanings of symptoms in cultures
• How much more likely are British African-Caribbean people to be diagnosed?

  Up to 9 times more likely
• What does symptom overlap suggest about schizophrenia?

  It may not exist as a distinct condition
• What are the implications of symptom overlap in schizophrenia diagnosis?


  • Difficulty in distinguishing schizophrenia from other disorders
  • Flawed classification and diagnosis
• What is a strength for the Diagnosis of Schizophrenia?

  Reliability

  • A psychiatric diagnosis is said to be reliable when inter-rater reliability and test-retest reliability can be established
  • Osório et al (2019) report excellent reliability for the diagnosis of schizophrenia in 180 people using the DSM-5, in which pairs of interviewers achieved inter-rater reliability of +0.97 and test-retest reliability of +0.92
  • This means that we can be reasonably sure that the diagnosis of schizophrenia is consistently applied
• What is a strength for Diagnosis of Schizophrenia?

  Validity within Diagnostic Systems

  • In Osório et al (2019), there was excellent agreement reported between clinicians when they used two measures to diagnose schizophrenia
  • Both measures were derived from the DSM system
  • This means that the criterion validity for diagnosing schizophrenia is actually good provided it takes place within a single diagnostic system
• What is a limitation for Diagnosis of Schizophrenia?

  Low Validity

  • Cheniaux et al (2009) had two psychiatrists independently assess the same 100 clients using the ICD-10 and DSM-4 criteria
  • Results found that 68 were diagnosed with schizophrenia under the ICD system and 39 under the DSM system
  • This suggests that schizophrenia is either over-diagnosed or under-diagnosed according to the diagnostic system, either way suggesting low criterion validity
• What is a limitation for Diagnosis of Schizophrenia?


  Co-morbidity

  • If conditions occur together a lot of the time, this calls into question the validity of their diagnosis and classification because they might actually be a single condition
  • Schizophrenia is commonly diagnosed with other conditions, such as depression or substance abuse
  • This is a problem for classification, as schizophrenia may not exist as a distinct condition and people who have been diagnosed with schizophrenia may have unusual cases of other conditions
• What is a limitation for Diagnosis of Schizophrenia?

  Gender Bias in Diagnosis

  • Since the 1980s, men have been diagnosed with schizophrenia more commonly than women, which may be because women are less vulnerable than men due to genetic factors
  • However, it seems more likely that women are underdiagnosed because they have closer relationships and get support, and so schizophrenic women are often better functioning than men
  • This underdiagnosis is a gender bias and means women may not be receiving treatment and services that might benefit them
• What is a limitation for Diagnosis of Schizophrenia?

  Culture Bias in Diagnosis

  • Some symptoms of schizophrenia have different meanings in different cultures, as for example, some people believe that voices are actually communications from ancestors
  • British people of African-Caribbean origin are up to 9 times as likely to receive a diagnosis as white British people, although people living in African-Caribbean countries are not, ruling out a genetic vulnerability
  • This means that British African-Caribbean people may be discriminated against a culturally-biased diagnostic system
• What is a limitation for Diagnosis of Schizophrenia?

  Symptoms Overlap

  • There is considerable overlap between the symptoms of schizophrenia and the symptoms of other conditions
  • In terms of classification, this suggests that schizophrenia and other disorders may be variations of a single condition, making it harder to distinguish
  • Symptom overlap means that schizophrenia may not exist as a distinct condition and that even if it does, it is hard to diagnose, and so both its classification and diagnosis are flawed