Schizophrenia

• Reliability and Validity of diagnosis

  Rosenham

  It is a field experiment.

  IV = made-up symptoms of the 8 pseudo (fake) patients,

  DV = psychiatrists' admission and diagnostic label of the pseudo patient.

  Participant observation - once admitted, the pseudo-patients kept written records of how the ward operated and how they personally were treated. They all reported the same symptom: hearing voices.

  • all puesdo-participants were admitted; only one not diagnosed with schizophrenia - remained 19 days average
  • 35/118 of real patients suspected the sanity of the pseudo-participants and voiced
• Reliability and Validity of diagnosis

  Rosenhan

  
  

  The study demonstrates both the limitations of classification and, importantly, the appalling conditions in many psychiatric hospitals. This has stimulated much further research and has led to many institutions improving their philosophy of care.

  
  

  EVAL

  Strengths

  • Ecologically valid.
  • Objective evidence from pseudo patients.
  • Quantitative and qualitative data.
  • Practical applications.

  Limitations

  • Ethics.
  • The pseudo patients experiences could differ from real patients as they knew they were not mentally ill.
• Reliability and Validity pf diagnosis

  Gender bias

  Longenecker et al. (2010)

  Schizophrenia diagnosis might suffer from gender bias because of the disproportionate number of men diagnosed with disorder in comparison to women.

  
  

  Cotton et al. (2009)

  Female patients appear to be more able to continue in work and have good family relationships. This better interpersonal functioning might lead to practitioners under-diagnosing schizophrenia in women.
• Reliability and validity

  Cultural bias

  Escobar - psychiatrists might be over-interpreting symptoms and distrusting the honesty of black people during diagnosis of schizophrenia - due to cultural differences - psychiatric profession dominated by white people so psychiatrist may struggle to relate to black patients' symptoms
• Schizophrenia


  A severe mental illness where contact with reality and insight are impaired, an example of psychosis
• Classification


  The process of organising symptoms into categories based on which symptoms cluster together in sufferers
• Diagnosis


  The assigning of a label of a disorder to a patient
• Classification systems used to diagnose schizophrenia

  • DSM (Diagnostic and Statistical Manual)
  • ICD (International Classification of Diseases)
• Positive symptoms


  An excess or distortion of normal functions, including hallucinations and delusions
• Hallucinations


  • Usually auditory or visual perceptions of things that are not present
  • Imagined stimuli could involve any of the senses
  • Voices are usually heard coming from outside the person's head giving instructions on how to behave
• Delusions


  • False beliefs, usually the person has convinced him/herself that he/she is someone powerful or important
  • Delusions of being paranoid, worrying that people are out to get them
• Negative symptoms


  A diminution or loss of normal functions such as psychomotor disturbances, avolition, disturbances of mood and thought disorders
• Thought disorder

  • Breaks in the train of thought and the person appears to make illogical jumps from one topic to another (loose association)
  • Words may become confused and sentences incoherent (word salad)
  • Broadcasting - a person believes their thoughts are being broadcast to others
• Avolition


  • Lack of volition (i.e. desire): in which a person becomes totally apathetic and sits around waiting for things to happen
• Reliability


  The level of agreement on the diagnosis by different psychiatrists across time and cultures; stability of diagnosis over time given no change in symptoms
• Diagnosis of schizophrenia is difficult as the practitioner has no physical signs but only symptoms (what the patient reports) to make a decision on
• Comorbidity describes people who suffer from two or more mental disorders, which makes it more difficult to confidently diagnose schizophrenia
• Some behavior which was regarded as psychotic in males was not regarded as psychotic in females, indicating gender bias in diagnosis
• Validity


  The extent to which schizophrenia is a unique syndrome with characteristics, signs and symptoms
• Neurocognitive deficits in basic functions such as memory, attention, central executive and problem solving skills may combine to have an outcome which we are labelling "Schizophrenia" as if it was the cause when in fact it is simply an umbrella term for a set of effects
• David Rosenhan's experiment involving Pseudopatients led to 8 normal people being kept in hospital despite behaving normally, suggesting doctors had no valid method for detecting schizophrenia
• Cultural relativism and variations in diagnosis is one of the biggest controversies in relation to classification and diagnosis
• African Americans and those of Afro-Caribbean descent are more likely to be diagnosed with schizophrenia than their white counterparts, but diagnostic rates in Africa and the West Indies is low - Western over diagnosis is a result of cultural norms and the diagnosis lacks validity
• Family studies


  Determine whether biological relatives of individuals with schizophrenia are similarly affected more often than non-biological relatives
• Identical (monozygotic) twins

  • One fertilised egg (ovum) splits and develops two babies with exactly the same genetic information
• Fraternal (dizygotic) twins


  • Two separate eggs (ova) are fertilized and develop into two genetically distinct individuals
• MZ twins have a 48% risk of getting schizophrenia whereas DZ twins have a 17% risk rate, showing the higher the degree of genetic relativeness, the higher the risk
• First-degree relatives of those with schizophrenia are 18 times more at risk than the general population
• Genetics are only partly responsible for schizophrenia, otherwise identical twins would have 100% concordance rates
• Family, twin and adoption studies must be considered cautiously because they are retrospective, and diagnosis may be biased by knowledge that other family members may have been diagnosed
• Schizophrenia is a multi-factorial trait as it is the result of multiple genes and environmental factors
• Dopamine hypothesis


  Schizophrenia is caused by an excessive amount of the neurotransmitter dopamine, leading to too many messages being transmitted
• Autopsies have found that there are generally a large number of dopamine receptors and an increase in the amount of dopamine in certain brain regions in schizophrenic patients
• It is not clear whether the raised dopamine levels are the cause or the result of schizophrenia, suggesting a problem with establishing cause and effect
• Some studies have found no difference between schizophrenics' levels of dopamine compared with non-schizophrenics, criticizing the dopamine hypothesis
• Autopsies have found that there are generally a large number of dopamine receptors (Owen et al., 1987) and there was an increase in the amount of dopamine in the left amygdale (falkai et al. 1988) and increased dopamine in the caudate nucleus and putamen (Owen et al, 1978)
• Is the raised dopamine levels the cause of the schizophrenia, or is it the raised dopamine level the result of schizophrenia?

  It is not clear which comes first
• The dopamine hypothesis is biologically deterministic as it does not account for freewill
• Neural correlates


  • Patterns of structure or activity in the brain that occur in conjunction with schizophrenia
• People with schizophrenia have abnormally large ventricles in the brain