Schizophrenia Flashcards
Background Information - 4 Points
- Affects 1% of the population
- More commonly diagnosed in men than women
- More commonly diagnosed in cities than in the countryside
- More commonly diagnosed in working class than middle class people
Definition of Schizophrenia
A severe mental illness where contact with reality and insight are impaired - an example of psychosis
Definition of Classification of a Mental Disorder
The process of organising symptoms into categories based on which symptoms cluster together in sufferers
Definition of Positive Symptoms
Atypical symptoms experienced in addition to normal experiences
Definition of Negative Symptoms
Atypical symptoms representing the loss of a regular experience
What are the Two Main Systems for Classifying Mental Disorders?
WHO’s ICD-10 and the American Psychiatric Association’s DSM-5
What does ICD-10 Stand For?
International Classification of Disease - Edition 10
What Does DSM-5 Stand For?
Diagnostic and Statistical Manual - Edition 5
How Does the DSM-5 Classify Schizophrenia?
Criterion A, B and C
Criterion A of the DSM-5 Classification System
Need two or more symptoms but only need one symptom if delusions are bizarre or hallucinations consist of a voice running commentary on behaviour or two voices conversing
5 Symptoms of DSM-5 Criterion A
- Delusions
- Hallucinations
- Disorganised speech, such as frequent derailment or incoherence
- Grossly disorganised or catatonic behaviour
- Negative symptoms, such as affective flattening, logia, or avolition
Criterion B of the DSM-5 Classification System
For a significant portion of the time since onset, one or more major ares of functioning such as work, interpersonal relationships or self-care are markedly below the level achieved prior to onset
Criterion C of the DSM-5 Classification System
- Continuous signs of disturbance persist for at least 6 months
- 6 month period must include at least 1 months of symptoms that meet Criterion A
- During non-active periods, disturbance may be limited to negative symptoms or two or more symptoms in Criterion A in attenuated form, such as odd beliefs or unusual perceptual experiences
3 Subtypes of Schizophrenia Recognised by the ICD - 10
- Paranoid schizophrenia
- Hebephrenic schizophrenia
- Catatonic schizophrenia
Paranoid Schizophrenia
Powerful hallucinations and delusions with relatively few other symptoms
Hebephrenic Schizophrenia
Primarily negative symptoms
Catatonic Schizophrenia
Disturbance to movement or immobile or inactive
2 Types of Symptoms
- Positive symptoms
- Negative symptoms
3 Positive Symptoms
- Hallucinations
- Delusions
- Affective flattening
3 Negative Symptoms
- Avolition
- Speech poverty
- Anhedonia
Hallucinations - 4 Points
- Unusual sensory experiences
- Some related to events in the environment (distorted representations) and some bear no relationship to the environment
- Can include voices heard talking to/commenting on the sufferer and are often critical
- Hallucinations can be experienced in relation to any sense
Delusions - 5 Points
- Irrational beliefs and a strong crossover with paranoia
- Come in a range of forms, such as delusions of grandeur and delusions of persecution
- May involve thinking part of the body is under external control
- Makes a sufferer behave in ways that seem sensible to them but bizarre to others
- Most sufferers are not aggressive and are more likely to be victims of violence, but some delusions can lead to aggression
Definition of Delusions of Grandeur
Thinking you have more importance than you do
Definition of Delusions of Persecution
Believing you are being mistreated
Avolition - 4 Points
- Sometimes called apathy
- Finding it hard to begin or keep up with goal-directed activity
- Sharply reduced motivation to carry out activities
- Andreason put forward the 3 signs of avolition
3 Signs of Avolition
- Poor hygiene and grooming
- Lack of persistence in work or education
- Lack of energy
Speech Poverty - 5 Points
- Changes in patterns of speech
- ICD-10 says this is a negative symptom due to reduction in the amount/quality of speech
- Sometimes comes with delays in verbal responses during conservations
- DSM-5 now puts emphasis on speech disorganisation - speech becomes incoherent or topic changes mid sentence
- DSM-5 now says this is a positive symptom whilst speech poverty is a negative symptom
Affective Flattening
Reduction in the range and intensity of emotional expression, voice tone, eye contact and body language
Anhedonia - 2 Points
- Loss of interest or pleasure in all or almost all activity, or lack of reactivity to normally pleasurable stimuli
- Can experience physical or social anhedonia
Schizophrenia Classification and Diagnosis A03 - Reliability - 4 Points
- Inter-rater reliability in relation to schizophrenia involves whether two or more mental health professionals come to the same diagnosis for the patient
- Cheniaux et al - had 2 psychiatrists independently diagnose 100 patients using DSM and ICD criteria and found poor inter-rater reliability
- One psychiatrist diagnosed 26 with Sz using DSM and 44 using ICD
- Other psychiatrist diagnosed 13 using DSM and 24 using ICD
Schizophrenia Classification and Diagnosis A03 - Validity - 4 Points
- For mental disorders, there are many validity issues to be considered
- A standard way to assess the validity of diagnosis is criterion validity - do different assessment systems arrive at the same diagnosis for a patient
- From the Cheniaux study, we can see a patient with Sz is much more likely to be diagnosed using ICD than using DSM
- Either DSM under-diagnoses or ICD over-diagnoses
Schizophrenia Classification and Diagnosis A03 - Symptom Overlap - 5 Points
- Considerable overlap between symptoms of Sz and bipolar disorder
- Both Sz and BPD involve positive symptoms like delusions and negative symptoms like avolition
- Leads to the question over validity of classification/diagnosis
- Under ICD, a patient may be diagnosed with Sz, but with same symptoms, some patients could be diagnosed with BPD according to DSM
- Could suggest that Sz and BPD could be one condition not two
Schizophrenia Classification and Diagnosis A03 - Co-Morbidity - 6 Points
- If 2 conditions occur together a lot of the time, we must question validity of diagnosis and classification, as it could be just one condition
- E.g. 1% of population experience Sz and 2-3% OCD, so we would expect only a few to have both
- Swets et al - meta analysis found at least 12% of patients with Sz fulfilled diagnostic criteria for OCD and about 25% displayed significant obsessive compulsive symptoms
- Buckley et al - found 50% with a diagnosis of Sz also have a diagnosis of depression, 47% substance abuse, 29% PTSD, and 23% OCD
- If 50% have depression as well, maybe we are just bad at telling the difference between the two conditions
- For classification , if severe depression looks a lot like Sz and vice versa, might it be better to see them as one condition
Definition of Co-Morbidity
Two or more conditions occur together
Schizophrenia Classification and Diagnosis A03 - Gender Bias in Diagnosis - 5 Points
- Longenecker et al - reviewed studies since the 80s, finding men have been diagnosed with Sz more often than women
- Men may be more genetically vulnerable, but a more plausible explanation is gender bias
- Cotton et al - female patients typically function better than male
- Might explain why some women have not been diagnosed where men with similar symptoms have been, as they are better at interpersonal functioning which may bias practitioners to under-diagnose Sz
- Women are generally better at masking symptoms
Schizophrenia Classification and Diagnosis A03 - Culture Bias in Diagnosis - 6 Points
- African Americans and English people of Afro-carribean origin are several times more likely than white people to be diagnosed with Sz
- Rates in Africa and West Indies are not particularly high so very unlikely to be genetically vulnerable but instead is the result of culture bias
- Positive symptoms like hearing voices may be more acceptable in African cultures
- Cultural beliefs in the communication with ancestors means they are more likely to acknowledge such experiences
- When reporting these symptoms to psychiatrists from different cultural traditions they can take a very ethnocentric approach
- Escobar - Many (white) psychiatrists over-interpret symptoms and distrust honesty of black people during diagnosis
Definition of Dopamine
A neurotransmitter which usually has an excitatory effect and is associated with the sensation of pleasure
Definition of Neural Correlates
Patterns of structure or activity in the brain that occur alongside an experience and may be implicated in the origins of it
Genetic Basis of Schizophrenia - Runs in Families? - 4 Points
- Noted for many years that schizophrenia is said to run in families
- Weak evidence for genetic basis to schizophrenia as families tend to share aspects of their environment too
- There have been systematic investigations of the extent to which greater genetic similarity is associated with concordance of schizophrenia
- These investigations, like Gottesman’s, suggest a strong relationship between the degree of genetic similarity and shared risk of schizophrenia
Genetic Basis of Schizophrenia - Candidate Genes - 6 Points
- Individuals are believed to be associated with a risk of inheritance
- Lots of different genes involved in increased risk (polygenic)
- Different studies have identified different candidate genes which suggests schizophrenia is aetiologically heterogenous
- Ripke et al - Combined previous data of genome-wide studies of schizophrenia
- Genetic make-up of 37,000 participants was compared to 113,000 controls
- 108 separate genetic variations associated with increased risk of schizophrenia
Definition of Aetiologically Heterogenous
Different combinations of factors can lead to same condition
Dopamine Hypothesis - 6 Points
- Can be seen as a neural correlate
- Neurotransmitters seem to work differently in the brain of a schizophrenia patient
- Dopamine (DA) thought to be involved
- DA important in functioning of many brain systems implicated in the symptoms of schizophrenia
- 2 parts involved - hyperdominergia in the sub cortex and hypdominergia in the cortex
Hyperdopaminergia in the Sub Cortex - 3 Points
- Original version of the DA hypothesis focused on the high levels/activity of DA in the sub cortex
- Sub cortex is a central area in the brain
- Excess of dopamine receptors in Broca’s areas could be associated with speech poverty and/or experience of auditory hallucinations
Hypodopaminergia in the Sub Cortex - 2 Points
- More recent version of DA hypothesis have focused on abnormal DA systems in the cortex
- Goldman-Rakic et al - identified role for low levels of DA in the pre-frontal cortex (responsible for thinking and decision making) in the negative symptoms of schizophrenia
Neural Correlates of Negative Symptoms - 5 Points
- Avolition involves loss of motivation and the anticipation of a reward
- Certain brain regions, like this one, are involved in this anticipation
- Abnormality of areas like this may be involved in the development of avolition
- Juckel et al - measured activity levels in ventral striatum in schizophrenia patients and found lower levels of activity than in control group
- Found negative correlation between activity levels in ventral striatum and severity of negative symptoms
Neural Correlates of Positive Symptoms- 3 Points
- Allen et al - scanned brain of those experiencing auditory hallucinations and compared them to control groups whilst identifying pre-recorded messages as their own or other’s speech
- Lower activation levels were found in sub cortex and VS in the hallucination groups
- They also made more errors than the control group
Biological Explanations for Schizophrenia A03 - Research Support for Genetic Vulnerability - 4 Points
- Very strong evidence from many sources, including Gottesman
- Tienari et al - adoption study of children of Sz sufferers still at heightened risk of Sz even if adopted into families with no history of Sz
- Also evidence at molecular level to show particular genetic variations significantly increase the risk of Sz, e.g. Ripke
- Overwhelming evidence that genetic factors have a big impact on vulnerability, even if not 100% responsible
Biological Explanations for Schizophrenia A03 - Mixed Evidence for DA Hypothesis - 7 Points
- Support from many sources for abnormal DA functioning in Sz
- Curran et al - DA agonists like amphetamines (increase in DA levels) make Sz worse and can produce Sz-like symptoms in non-sufferers
- On the other hand, antipsychotic drugs work by reducing DA activity
- Both kinds of study suggest an important role for DA in Sz
- Lindstroem et al - radioactive labelling studies have found chemicals needed to produce DA are taken up faster in brain of Sz patients than controls, which suggests they produce more DA
- Also evidence that DA cannot be a complete explanation - some genes identified in Ripke’s research code for production of other neurotransmitters, which means it seems likely DA is important but other neurotransmitters are likely to be important
- Lots of attention recently has shifted to another neurotransmitter called glutamate
Biological Explanations for Schizophrenia A03 - Correlation Causation Problem - 4 Points
- There are many neural correlates of Sz symptoms, both positive and negative
- Although studies can flag up brain systems that may not operate normally, there are still unanswered questions
- Does the unusual activity cause the symptoms or do the symptoms cause the unusual activity?
- Could another factor draw them together?
Biological Explanations for Schizophrenia A03 - The Role of Mutation - 4 Points
- Sz can take place even when there is no family history of the disorder
- One explanation for this is mutation in parental DNA
- Brown et al - demonstrated a positive correlation between parental age, which is associated with increase risk of sperm mutation, and risk of Sz
- Increase from 0.7% with fathers under 25 y/o to 2+% in under 50 y/o
Biological Explanations for Schizophrenia A03 - Role of Psychological Environment is Important but Unclear
Evidence supporting the role of biology in Sz is overwhelming but there is also evidence for an important role of environmental factors, including psychological ones like family functioning during childhood
Biological Treatments for Sz - Drug Therapies - 5 Points
- The most common Sz treatment involves the use of antipsychotic
- Antipsychotics can be taken in tablet, syrup form, or even as 2-4 weekly injections for those at risk of failing to take regular medication
- Can be required for short or long term
- Some may take them for a short course then stop use, and their symptoms never return
- Others may require them for life or face the likelihood that their Sz will recur
Definition of Antipsychotics
Drugs to reduce the intensity of symptoms, especially the positive symptoms of psychotic conditions
Definition of Typical Antipsychotics
The first generation of antipsychotic drugs used since the 50s, and they work as dopamine antagonists
Definition of Atypical Antipsychotics
Drugs for Sz developed after typical antipsychotics, and they target a range of neurotransmitters including dopamine and serotonin