Schizophrenia

• What is Schizophrenia (SZ)

  A psychosis disorder, suffered by 1% of the population, diagnosed in more men than women, more common in cities and more common in working class than the middle class
• ICD-10 criteria for SZ

  European criteria - Recognises a range of subtypes for SZ - 2 negative symptoms needed
• DSM-5 criteria for SZ

  Only one positive symptom needed - No subtypes - American
• Symptoms of SZ


  Positive: (add to the cognitive experience of the individual)

  - Hallucinations - unusual sensory experience, sometimes related to environment but others may bear no relationship from reality

  - Delusions - Irrational belief that have no basis in reality yet patients are unaware of this

  
  

  Negative: (reduce the cognitive experience of the individual)

  - Avolition - Loss of motivation which results in decreased activity levels (Andreason found 3 types of this - poor hygiene, lack of energy and lack of persistence)

  - Speech poverty - Reduction in speech either by amount or quality, sometimes demonstrating a delay in responses
• Cheniaux et al


  2 psychiatrists independently diagnose 100 patients using the DSM & ICD criteria

  Overall inter-rater reliability was poor

  Psychiatrist 1 - 13 DSM, 24 ICD

  Psychiatrist 2 - 26 DSM, 44 ICD
• Biological explanations of SZ - Neural correlates

  Measurements of the structure or function in the brain in terms of behaviour.

  
  

  Neural correlates of negative symptoms:

  Juckel et al - Low levels of activity in the ventral striatum which is involved in motivations. Negative correlation between activity levels and severity of SZ

  
  

  Neural correlates of positive symptoms:

  Allen et al - Lower activation levels in the superior temporal gyrus (auditory processing) and anterior cingulate gyrus in patients with sz.
• Biological therapies for SZ - Typical antipsychotics

  Chlorpromazine - Acting as an antagonist in the dopamine system reducing the act of dopamine by blocking its receptors

  Strong association between the use of typical antipsychotics and dopamine hypothesis, reducing hallucinations
• Biological therapies for SZ - Atypical antipsychotics

  Clozapine - Risk of fatal blood condition. Binds to dopamine receptors as well as serotonin and glutamate to improve mood, reducing rates of depression (comorbidity). May improve cognitive function and typically given to those at high risk of suicide

  
  

  Risperidone - Binds to serotonin and dopamine receptors, stronger binding than for clozapine. Much more effective in smaller doses and there is less side effects (more modern)
• Psychological explanations of SZ - Cognitive

  Reduced processing in the ventral striatum - leading to negative symptoms and temporal & cingulate gyri lead to hallucinations. Reduced levels of information processing suggests cognition is more likely to be impaired

  
  

  Frith identified 2 dysfunctional thought processes in SZ:

  Metarepresentation - A disruption in the ability to recognise their own thoughts and actions resulting in hallucinations and delusions

  Central control - Disorganised SZ's suffer from the inability to suppress automatic thoughts and speech triggered by thoughts
• AO3 - Psychological explanations of SZ


  Schizophrenogenic mother is highly socially sensitive

  Read et al - Meta-analysis on 46 studies of child abuse and schizophrenia - 69% adult women had history of sexual or physical abuse (limited sample)

  Difficult to know if expressed emotion is cause or consequence of SZ

  Many offer as just risk factors/vulnerability but don't offer anything else alongside it

  
  

  Stirling et al - 30 SZ patients with 18 in control. Completed a range of cognitive tasks such as the stroop task where SZ patients took 2x as long (lacks mundane realism)
• Psychological therapies for SZ

  CBT - Commonly used for SZ patients, lasting between 5 and 20 sessions. Aims to identify irrational thoughts (delusions) and how to change them by setting homework for scientific evidence for their beliefs.

  Turkington et al - CBT effectively helped a patient who believed the mafia were watching them.

  
  

  Family therapies - Takes place within families to improve the quality of communication and interaction between them.

  Pharoah et al - Range of strategies aiming to improve function of family which reduced expressed emotion while also increasing the compliance with medication

  
  

  Token economies - Used to manage behaviour (typically maladaptive behaviour - ones which negatively affect someone's ability to live) to improve life quality. Rewards can be sweets, cigarettes or magazines
• AO3 - Psychological therapies for SZ

  Jauhar et al - Meta-analysis of CBT found significant impact but on a small scale

  Pharoah et al - Moderate evidence for the use of family therapies (Both offer a lack of control groups)

  All therapies mentioned improve the well being and quality of life with SZ patients but it does not offer a cure to SZ (though some theories such as DB suggest this is useful)

  Ethical issues involved in token economies as those with severe symptoms cannot access the rewards

  Environmentally reductionist
• Interactionist approach to SZ

  Meehl's model - If someone carries a "schizogene", they develop a biology based schizotypic personality which gives them great sensitivity to stress. Chronic stress through childhood and adolescence can lead to the development of SZ

  
  

  Ripke et al - No one single schizogene as they found 108 variations, diathesis model includes factors such as psychological trauma which becomes the diathesis and not the stresser

  Read et al - Early trauma laters the development of the brain, specifically the HPA (stress symptom)

  
  

  Houston et al - The modern understanding of stress relating to SZ is anything which could trigger it

  Lots of research has been done between cannabis use and SZ. Common use of cannabis increases the risk of developing SZ by 7x

  Cannabis interferes with the dopamine system and has seen to have cognitive effects though not all users develop SZ

  
  

  Turkington et al - It is possible to believe biological causes behind SZ but use CBT to relieve psychological symptoms
• AO3 - Interactionist approach to SZ

  Tienari et al - 1900 adopted children with SZ mother's between 40 year period. Adopted parents were assessed for child-rearing style. Those with highly critical and confrontational child rearing styles were implicated in the development of SZ in children with high genetic risk (Biology has more influence)

  
  

  Tarrier et al - Randomly allocated 315 patients to either have interactionist treatment (CBT), medication and supportive counselling or only medication. Combination groups showed lower symptom levels though no difference in hospital readmission rate

  
  

  Houston et al - Childhood sexual trauma was vulnerability factor and cannabis use is a trigger. Old idea of diathesis as biology and stress is too simplistic (reductionist)

  
  

  Lots of evidence linking SZ to stress yet we are not there with understanding the mechanisms behind symptoms appearing