Schizophrenia

• what are positive symptoms of schizophrenia?

  Additional experiences that an individual does not usually have

  They are called positive because you are adding something to your behaviour that does not usually exist

  -Hallucinations

  -Delusions
• what are hallucinations?


  - unusual experiences linked to one or more sense e.g. a person can see, hear, smell, taste or feel something that is not actually present

  - usually auditory or visual but can be any sense
• what are delusions?


  - these are irrational beliefs that a person has about something and can take a range of different forms

  - they will seem very real to the person

  -- delusions of persecution are when a person believes that something or someone is out to hurt them

  -- delusions of grandeur are when a person believes that they are powerful and or important
• what is speech poverty (alogia)?


  - When a person has a reduction in the amount or quality of their speech

  - They may speak infrequently and lack fluency so not make sense

  - Give brief responses during a conversation
• What are negative symptoms of schizophrenia?


  Symptoms that involve the loss of usual abilities and experiences.

  They are called negative symptoms as it's subtracting behaviours from a person

  - avolition

  - speech poverty (alogia)
• what is avolition?


  - this is when a person fails to engage in a goal directed activity

  - they stop making an effort to do something

  - for example, they appear to have no motivation to do anything, may stop washing, or stop going to work or not brushing teeth / getting dressed
• how is schizophrenia diagnosed?

  DSM-5

  - 2 or more symptoms duration of 6 months or more or one sever symptom for at least a month

  ICD-11

  - can be diagnosed with 2 or more negative symptoms only - for at least a month
• what is schizophrenia prognosis?

  'rule of thirds'

  - 1/3 recover more or less completely

  - 1/3 episodic impairment

  - 1/3 chronic decline

  with treatment about 60% if patients manage a relatively normal life
• what is reliability for schizophrenia?

  - reliability means consistency

  - an important measure of reliability is inter-rater reliability, the extent to which different assessors agree on their assessments
• what is validity?


  - validity means if we are measuring what we intend to measure

  - one standard way to assess validity of a diagnosis is criterion validity - do different assessment systems arrive at the same diagnosis for the same person?
• what was cheniaux et al research for reliability?

  - 2 psychiatrists independently diagnosed 100 people using both DSM and ICD criteria

  - inter-rater reliability was poor, with one psychiatrist diagnosing 26 with schizophrenia according to DSM and 44 according to ICD, the other diagnosing 13 according to DSM and 24 according to ICD

  - this poor reliability is a weakness of diagnosis of schizophrenia
• what is cheniaux et al study for validity?

  - schizophrenia is much more Riley to be diagnosed using ICD than DSM

  - this suggests that schizophrenia is either over diagnosed in ICD or under-diagnosed in DSM

  - this is poor validity - weakness of diagnosis
• what is comorbidity?


  - a patient suffers from two or more mental disorders at the same time
• what research does Buckley et al dot or comorbidity?

  - 50% schizophrenia patients also have a diagnosis of depression

  - 47% schizophrenia patients also have a diagnosis of substance abuse
• how is comorbidity an issue?

  - if conditions occur together a lot of the rime then this calls into question the validity of their diagnosis and classification because they might actually be a single condition

  - this has implications for treatments
• what is symptom overlap for schizophrenia?

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

  - for example, both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative symptoms like avolition

  - this again calls into question the validity of both the classification and diagnosis of schizophrenia

  - under ICD a person might be diagnosed with schizophrenia - however many of the same individuals would receive a diagnosis of bipolar disorder according to DSM criteria

  - may suggest that schizophrenia and bipolar disorder may not be two different conditions
• what research did Longenecker et al do for gender bias?

  - reviewed studies of the prevalence of schizophrenia and concluded that since the 1980s men have been diagnosed with schizophrenia more often than women

  - this may be simply because men are more genetically vulnerable to developing schizophrenia than women

  - but, another explanation is gender bias in the diagnosis
• what does cotton et al say for gender bias in diagnosis?

  - appears that women typically function better than men, being more likely to wrk and have a good family relationships

  - this high functioning may explain why some women have not been diagnosed with schizophrenia
• what is culture bias in diagnosis?

  - African Americans and English people of afro-carribean origin are several times more likely than white people to be diagnosed

  - given that rates in Africa and the West Indies are not particularly high, so this is not due to genetically vulnerability

  - one issue is that positive symptoms such as hearing voices may be more acceptable in culutures because of cultural beliefs in communication with ancestors, so people are more ready to acknowledge these experiences

  - when reported to a psychiatrist of a different cultural tradition these experiences are likely to be seen as bizarre and irrational
• what did Gottesman say about schizophrenia in families?


  - general population = 1%

  - DZ twins = 17%

  - MZ twins = 48%

  - weak evidence as families tend to share aspects of their environment as well as many of their genes
• what adoption study did Tienari et al conduct to support genetic vulnerability?

  - adoptees at high genetic risk are significantly more sensitive to adverse vs 'healthy' rearing patterns in adopted families than are adoptees at low genetic risk

  - shows that children of people with schizophrenia are still at heightened risk of schizophrenia if adopted into families with no history of schizophrenia
• what are candidate genes in schizophrenia?

  - schizophrenia is polygenic - a number of genes are needed to increase risk

  - different studies show different genes work on combination - aetiologically heterogeneous

  - PCM1 gene

  - TNF and NOTCH4 genes

  - there is an association between these candidate genes and susceptability to schizophrenia
• how does Ripke et al study support candidate genes?


  - carried out huge study combining all previous data from genome-wide studies of schizophrenia

  - the genetic make up of 37,000 people diagnosed with schizophrenia and was compared to 113,000 controls

  - 108 genetic variations were associated with increased risk of schizophrenia

  - genes associated included those coding for the functioning of a number of neurotransmitters including dopamine
• what is dopamine hypothesis?

  - neurotransmitters appear to work differently in the brain of a person with schizophrenia

  - in particular dopamine is widely believed to be involved

  - dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of schizophrenia
• what is hyperdopaminergia in the sub cortex?


  - the original version of the dopamine hypothesis focused on the possible role of high levels or activity of dopamine in the sub cortex

  - for example, an excess of dopamine receptors in brocas area may be associated with poverty of speech and / or the experience of auditory hallucinations
• what is hypodomainergia in the cortex?

  - more recent versions of the dopamine hypothesis have focused instead of abnormal dopamine systems in the brains cortex

  - Goldman-Rakic et al have identified a role of low levels of dopamine in the prefrontal cortex and negative symptoms of schizophrenia
• how does Curran et al support the dopamine hypothesis?

  - dopamine agonists like amphetamines that increase the levels of dopamine make schizophrenia worse and can produce schizophrenia like symptoms in people not diagnosed by schizophrenia
• how does Tauscher et al support the dopamine hypothesis?

  - antipsychotic drugs work by reducing dopamine activity

  - however, treatment aetiology fallacy = just because a treatment works effectively doesn't mean that the underlying cause of schizophrenia has been identified
• what are neural correlates?

  - measures of the structure or function of the brain that correlate with an experience, in this case schizophrenia

  - both positive and negative symptoms have neural correlates
• what are neural correlates of negative symptoms?

  - one negative symptom avolition involves the loss of motivation

  - motivation involves the anticipation of a reward and certain regions of the brain, for example, the ventral striatum, are believed to be particularly involved in this anticipation

  - it therefore follows that abnormality of areas like the ventral striatum may be involved in the development of avolition
• how does Jackal et al support neural correlates of negative symptoms?


  - have measured activity levels in the ventral striatum in schizophrenia an found lower levels of activity than those observed in controls

  - they observed a negative correlation between activity levels in the ventral striatum and the severity of the overall negative symptoms

  - so activity in the ventral striatum is a neural correlate of negative symptoms of schizophrenia
• what are neural correlates of positive symptoms?

  - Allen et al scanned the brains of people experiencing auditory hallucinations and compared them to a control group whilst they identified prerecorded speech as theirs or others

  - lower activation levels in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group, who also made more errors than the control group

  - so can say that reduced activity in these two areas of the brain is a neural correlate of auditory halluccination
• how is correlation not causation a limitation?

  - does the unusual activity in a region of the brain cause the symptom?

  - for example, the correlation between levels of activity in the ventral striatum and negative symptoms of schizophrenia - it may be that something is wrong in the striatum is causing the negative symptoms

  - however it is possible the negative symptoms themselves mean that less information passes through the striatum, resulting in reduced activity
• what is family dysfunction?

  abnormal processes within a family such as poor family communication, cold parenting and high levels of expressed emotion. These may be risk factors for both the development and maintenance of shcizophrenia
• how was the schizophrenogenic mother explanation developed ?

  - Fromm-Reichmann proposed a psychodynamic explanation based on the accounts she heard from her clients about their childhoods

  - she noted that many of her clients spoke of a particular type of parent, which she called the schizophrenic mother
• what is the schizophrenogenic mother explanation?

  - according to Fromm- Reichmann, the schizophrenogenic mother is cold, rejecting and controlling and tends to create a family climate characterised by tension and secrecy

  - this leads to distrust that later develops into paranoid delusions and ultimately schizophrenia
• what is the double-blind theory explanation?

  - Bateson et al agreed that family climate is important in the development of schizophrenia but emphasised the role of communication style within a family

  - the developing child regularly finds themselves trapped in situations where they fear doing the wrong thing, but receive mixed messages about what this is, and feel unable to commont on the unfairness of this situation or seek clarification

  - when they 'get it wrong' (which is often) the child is punished by withdrawal of love

  - this leaves them with an understanding of the world as confusing and dangerous, and this is reflected in symptoms like disorganised thinking and paranoid delusions
• what is the expressed emotion explanation for schizophrenia?

  - expressed emotion is the level of emotion, in particular negative emotion, expressed towards a person with schizophrenia by their carers. Contains several elements :

  -- verbal criticism of the person, occasionally accompanied by violence

  -- hostility towards the person, including anger and rejection

  -- emotional over-involvement in the life of the person, including needless self-sacrifice

  - these high levels of expressed emotion in carers directed towards the person are a serious source of stress for the patient

  - this is primarily an explanation for relapse in people with schizophrenia

  - however, it has also been suggested that it may be a source of stress that can trigger the onset of schizophrenia in a person who is already vulnerable due to their genetic make up
• what is the cognitive explanation for schizophrenia?


  - schizophrenia is associated with several types of abnormal information processing, and these can provide possible explanations for schizophrenia as a whole

  - Firth et al identified two kinds of dysfunctional thought processing that underlie some symptoms :

  Metarepresentations

  Central control
• what is metarepresentation as a cognitive explanation?


  - the cognitive ability to reflect on thoughts and behaviour

  - this allows us insight into our own intentions and goals

  - it also allows us to interpret the actions of others

  - dysfunction in metarepresentation would disrupt our ability to recognise our own actions and thoughts as being carried out by ourselves rather than someone else

  - this would explain hallucinations of voices and delusions like thought insertion