Diagnosis & Classification of Schizophrenia

• Schizophrenia


  - a severe psychological disorder in which thoughts and emotions are so impaired that contact is lost with reality

  
  

  - most often diagnosed ages 15 - 35

  
  

  - classic schizophrenia symptoms include:

  . delusions: belief in something that is not/can't be true

  . hallucinations: experiencing stimuli that are not present

  
  

  - there are other symptoms of schizophrenia however they vary from individual to individual
• Diagnosis & Clarification


  - diagnosis and classification are interlinked; to diagnose a disorder we need to distinguish it from another

  
  

  - this is done by identifying clusters of symptoms that occur together and classifying this as one disorder

  
  

  - there are 2 major systems for the classification of mental disorder:

  . International Classification of Disease (ICD-10)

  . Diagnostic and Statistical Manual Edition 5 (DSM-5)
• Positive Symptoms: Schizophrenia


  - positive symptoms: symptoms experienced in addition to normal function

  
  

  - positive symptoms of schizophrenia:

  . hallucinations

  . delusions
• Negative Symptoms: Schizophrenia


  - negative symptoms: symptoms which impairs normal/usual function

  
  

  - negative symptoms of schizophrenia:

  . avolition

  . speech poverty
• Hallucinations


  - sensory experiences with no basis in reality or distorted perceptions of things already there
• Delusions


  - beliefs that have no basis in reality
• Avolition


  - also called apathy

  
  

  - loss of motivation to carry out tasks leading to lowered activity levels
• Speech Poverty


  - reduced frequency/quality of speech
• Co-morbidity: Schizophrenia


  - the occurrence of 2 conditions together

  
  

  - 2 conditions frequently being diagnosed together can call into question the validity of classifying the 2 disorders separately
• Symptom Overlap


  - when 2 or more conditions share symptoms

  
  

  - this can call into question the validity of classifying the 2 disorders separately
• Good Reliability: Strength


  - the diagnosis of schizophrenia is reliable (consistent)

  
  

  - clinicians assess reliability using inter-rater and test-retest reliability

  
  

  - (Osório et al, 2019) reported excellent reliability for the diagnosis of schizophrenia in 180 individuals using the DSM-5

  
  

  - Pairs achieved an inter-rater reliability score of +0.97 and test-retest reliability of +0.92

  
  

  - this means can be reasonably sure that the diagnosis of schizophrenia is consistently applied
• Low Validity: Limitation


  - schizophrenia has low criterion validity

  
  

  - (Cheniaux et al, 2009) had 2 psychiatrists independently assess the same 100 clients using ICD-10 and DSM-4

  
  

  - 68 were diagnosed with schizophrenia using the ICD system and 39 under the DSM

  
  

  - suggests schizophrenia is over or under-diagnosed according to the diagnostic system
• Low Validity: Counterpoint


  - (Osório et al, 2019) reported there was excellent agreement between clinicians when they used 2 both the ICD and the DSM

  
  

  - criterion validity for diagnosing schizophrenia is actually good when it takes place in a single diagnostic system
• Co-morbidity: Limitation

  - schizophrenia is often co-morbid with other conditions

  
  

  - the occurrence of 2 conditions could question the validity of their diagnosis and classification; potentially being a single diagnosis

  
  

  - (Buckley et al) found:

  . 50% of individuals diagnosed with schizophrenia also have depression

  . 47% have a co-morbidity with substance abuse

  . 23% have a co-morbidity with OCD

  
  

  - this means schizophrenia may not be a distinctive condition
• Gender Bias: Limitation


  - schizophrenia diagnosis

  
  

  - (Fischer & Buchanan) since the 1980s men have been diagnosed with schizophrenia more commonly than women (1.4 : 1)

  
  

  - women are likely to be under-diagnosed because they have closer relationships and hence get support; leading to them functioning better (Cotton et al, 2009)

  
  

  - this means women may not be getting the treatment or services that benefit them
• Cultural Bias: Limitation


  - some symptoms of schizophrenia may be interpreted differently by different cultures

  
  

  - e.g. hearing voices is interpreted as communication with ancestors

  
  

  - (Pinto & Jones, 2008) British people of Afro-Caribbean descent are 9x more likely to be diagnosed with schizophrenia than their white counterparts

  
  

  - this is not the case for those living in Afro-Caribbean countries eliminating genetic vulnerability

  
  

  - this means people from different cultures may be discriminated against by a culturally-biased diagnostic system
• Symptom Overlap: Limitation


  - there's considerable overlap between the symptoms of schizophrenia and other conditions

  
  

  - e.g. schizophrenia and bipolar disorder share the positive symptoms of delusions and the negative one of avolition

  
  

  - in terms of classification this means that they may simply be variations of a single condition

  
  

  - this makes schizophrenia's diagnosis and classification flawed and hard to distinguish