schizophrenia

• What is schizophrenia?


  A mental disorder characterised by a profounddisruption of cognition and emotion, which affects language, thought, perception and sense of self
• What two systems are used to diagnose schizophrenia?

  1. The Diagnostic and statistical Manual of Mental disorders edition 5 (DSM-V)

  2. The International Classification system for diseases edition 10 (ICD-10)
• What is classification?


  Defining mental disorders on the basis of their characteristics or symptoms
• What is diagnosis?


  The process of identifying and determining a disorder by it's symptoms through the use of an assessment
• What is meant by ensuring the diagnosis of schizophrenia is reliable?

  When the criteria is used by another psychiatrist they come to the same conclusion and diagnosis
• What is meant by ensuring the classification of schizophrenia is valid?

  The criteria is accurately measuring schizophrenia and not another disorder
• What is the DSM-V criteria for schizophrenia?

  One positive symptom: delusions, hallucinations or speech disorganisation must be present for six months or one month if ''active
• What is the ICD-10 criteria for schizophrenia?

  Two or more negative symptoms/positive symptoms
• What does the ICD-10 recognise that the DSM-V does not?

  ICD recognises a range of subtypes:

  - Paranoid schizophrenia is characterised by power delusions and hallucinations

  - Catatonic schizophrenia is characterised by a disturbance of movement
• How does the criteria for schizophrenia raise an issue for validity?

  ICD-10 and DSM-V define schizophrenia differently so may not accurately be measuring schizophrenia
• How does the criteria for schizophrenia raise an issue for reliability?

  Different psychiatrists using different criteria will have different diagnoses
• What are the positive symptoms of schizophrenia?

  These are symptoms an individual experiences in addition to what they would consider ordinary existence/daily experiences

  E.g. hallucinations and delusions
• What are the negative symptoms of schizophrenia?

  These are symptoms when an individual haslost an aspectof what we would consider ordinary existence/every day experiences are reducedE.g. avolition, speech poverty
• What are delusions?


  - Bizarre beliefs that seem to be real to the person but are not.

  - They are fixed and hard to change

  - These can be paranoid or may involve inflated beliefs about that person's power
• What are hallucinations?


  - Bizarre, unreal perceptions of the environment

  - They are usually auditory but can also be visual or tactile
• What is speech poverty?

  - It involves reduced frequency and quality of speech

  - Characterised by not being able to express complicated ideas and speaking very slowly

  - This is thought to indicate slowing or blocked thoughts
• Evaluate the classification and diagnosis of schizophrenia

  - Subjectivity of diagnosis

  - Reliability

  - Cultural bias

  - Co-morbidity

  - Symptom overlap

  - Gender bias
• Briefly describe Rosenhan's experiment: 'Being sane in insane places'

  - The aim was to see how well psychiatrists could distinguish between real patients with schizophrenia and 8 sane patients

  - 8 pseudo patients presented with a single symptom (hearing voices)

  - Once admitted they acted normally and co-operated with staff.

  - All 8 psuedo patients were admitted to 12 hospitals across the U.S and were never detected. They were released with a diagnosis of 'Schizophrenia in remission'.
• Evaluate Rosenhan's study


  - Methodlogical issues: small sample size

  - Implications for patients if diagnosis is not valid: once labelled with a condition, patients find it very hard to escape the label
• Subjectivity of diagnosis


  - Rosenhan showed that people could fake their way into a psychiatric hospital and that staff were too quick to conclude that a person is schizophrenic- This suggests the diagnosis of schizophrenia is subjective. Even with the symptoms set out,the behaviour of an individual is always open to interpretation. Diagnosis lacks validity as the pseudo patients were incorrectly diagnosed- Classification is not accurately measuring schizophrenia
• Lack of relaibility in diagnosis of schizophrenia

  - Elie Cheniaux et al had two psychiatrists independently diagnose 100 patients using both DSM and ICD. They found that one psychiatrist diagnosed 26 with schizophrenia according to the DSM and 44 according to the ICD. The other psychiatrist diagnosed 13 according to the DSM and 24 with the ICD-Inter-rater reliabilitywas poor. Both psychiatrists did not come to the same conclusions for the same patients. Diagnosis is subjective and lacks scrutiny.
• Lack of relaibility in diagnosis of schizophrenia: Counter-argument

  - Diagnosis may actually have excellent reliability. Osorio et al found an inter-rater reliability of +0.97 and test retest of +0.92 when pairs of interviewers assessed 180 individuals using the DSM-V
• Cultural bias: Evidence

  - According to the DSM-V and ICD-10 symptoms of hallucinations can warrant a diagnosis of schizophrenia

  - This criteria does not take into account differences in culture. African Americans and people of Afro-Caribbean origin are more likely to be diagnosed with schizophrenia than White people.
• Cultural bias: Explanation


  - Symptoms such as hearing voices may be more acceptable in African cultures due to their belief in communication with their ancestors.- If the individual is speaking to a psychiatrist from a different culturethey are more likely to report such experiences as abnormaland could result in a diagnosis of schizophrenia when the patient does not suffer from schizophrenia
• Co-morbidity


  -Two disorders co-existand one might hide or contribute to the other- Patients with schizophrenia may also be diagnosed with depression or a personality disorder. This is a weakness as it raises an issue for thevalidity of diagnosis and classification- Schizophrenia may not exist as a separate condition (classification)- Some people may not have schizophrenia but instead a rare case of depression (diagnosis)
• Symptom overlap


  - Occurs when two or more conditions share symptoms.- Both schizophrenia and bipolar disorder involve positive symptoms such as delusions and negative symptoms such as avolition- Schizophrenia and bipolar disorder may not be 2 different conditions but a variation of one single disorder (classification)- It ishard to distinguish between the twowhich may lead to incorrect diagnoses
• Gender bias


  - Diagnosis is gender biased- Since the 1980s men have been diagnosed with schizophrenia more often than women (1.4:1)- Women may be underdiagnosed because they tend to havecloser relationships and get more support. This suggests women with schizophrenia are better functioning than men- However this means women may not be getting the right treatment or access to services
• What is the genetic explanation?

  That the closer two individuals are genetically, the more likely that both of them will develop schizophrenia
• Summarise the findings of Gottesman's study

  - Identical twins have a 48% chance of each twin developing schizophrenia

  - There is only a 2% chance of developing schizophrenia if an aunt has it
• What are candidate genes?

  - Individual genes that create vulnerability for schizophrenia

  - A number of individual genes increase the risk of schizophrenia

  - It appears schizophrenia is polygenic (influenced by multiple genes that work in combination)
• Research to support the genetic basis of schizophrenia

  -Stephen Ripke et alcarried out a large study combining data from previous research. The genetic make-up of 137,000 patients was compared to that of 113,000 controls. 108 separate genetic variations were associated with increased risk of schizophrenia-Benzel et alidentified three genes: COMT, DRD4, AKT1 have all been associated withexcess dopaminein specific D2 receptors, leading to positive symptoms such as delusions and hallucinations.
• What are the implications of the genetic explanation of schizophrenia?

  -Alerts someone that they are of higher riskof developing schizophrenia- Can avoid stressful occupations or drug use that might trigger the condition. If the symptoms of schizophrenia are recognised early then the disorder can be managed more effectively
• What is the dopamine hypothesis?

  Abnormal activity at dopamine receptors plays a crucial role in the development of schizophrenia
• What does the original dopamine hypothesis suggest?

  - Hyperdopaminergia in the subcortex e.g. too many dopamine receptors in Broca's area

  - Associated with positive symptoms such as auditory hallucinations
• What does the updated dopamine hypothesis suggest?

  - Hypodopaminergia in the cortex e.g. low levels in the pre-frontal cortex (responsible for thinking and decision making)

  - Associated with negative symptoms

  - Genetic vulnerabilities and early experiences of stress may cause some people to be more sensitive to hyper/hypodopaminergia
• What implications does the dopamine hypothesis have on treatments for schizophrenia?

  - Development of antipsychotic drugs which block dopamine receptors, increase levels of dopamine and reduce symptoms of schizophrenia
• What are neural correlates?

  Patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience
• Neural correlates of positive symptoms

  -Allen et al, scanned the brains of patients experiencing auditory hallucinations and compared them to a control group while they identified either others or their own recorded speech.- Lower activation levels in thesuperior temporal gyrus and anterior cingulate gyruswere found in the hallucination group, who also made more errors than the control group. We can therefore say that reduced activity in these two areas of the brain isneural correlate of auditory hallucination
• Neural correlates of negative symptoms

  - Avolition is the loss of motivation- Motivation involves the anticipation for a reward and theventral striatumare believed to be involved in this anticipation- involved in the development of avolition. There must be abnormalities in this area.- Juckel et al found that activity in the ventral striatum is a neural correlate of negative symptoms
• Evaluate the biological explanation

  - Correlation-causation problem

  - Evidence for dopamine hypothesis

  - Multiple sources of evidence for genetic susceptibility