Schizophrenia Flashcards
What is SZ
- serious mental psychotic disorder
- characterised by profound disruption of cognition and emotion
What can SZ affect
- language
- thought and perception
- emotion
- sense of self
How many people suffer from SZ
- 1% of the population
- affects about 4 in 1000 people (Saha et al., 2005)
What is the onset for SZ
- between 15 and 35 years
Who does SZ affect more
- men than women
- cities than countryside
- working class than middle class
SZ is psychotic and not neurotic, what does psychotic mean
- mental illness causing abnormal thinking and perceptions
- people lose touch with reality and even sense of self
What happens to people suffering from SZ
- end up homeless or hospitalised
- not uncommon to commit or attempt suicide
What can be used to diagnose SZ
- DSM 5 (the Diagnostic and Statistical Manual of Psychiatric Disorders)
- ICD 11 (the International Classification of Diseases)
Where are the DSM and ICD used
- DSM is used in America
- ICD used in Europe and other parts of the world
How does diagnoses between the DSM and ICD differ
- DSM states you need at least 2 positive symptoms or 1 positive and 1 negative for a period of 1 month as well as extreme social withdrawal for 6 months
- ICD states you need to show 1 positive and 1 negative or 2 negative symptoms for at least 1 month
What are the types of SZ
- Type 1
- Type 2
Who made a distinction between the types of SZ
- Crow (1980)
What is Type 1 SZ
- characterised more by positive symptoms
- better prospects for recovery
What is Type 2 SZ
- characterised more by negative symptoms
- poorer prospects for recovery
What’s the difference between positive and negative symptoms
- positive add to an individual’s behaviour
- negative takes from an individual’s behaviour
What are examples of positive symptoms
- hallucinations
- delusions
- disorganised speech
- grossly disorganised or catatonic behaviour
What are hallucinations
- sensory experiences of stimuli that have no basis in reality or are distorted perceptions of things
- different types
What are the different types of hallucinations
- auditory; person experiences hearing voices making comments or talking to them in their head, normally criticising then
- visual; seeing things that are not real
- olfactory; smelling things that are not real
- tactile; touching things that are not there
What are delusions
- irrational, bizarre beliefs that seem real to the person with SZ
- can involve being an important historical, religious or political figure
- may also involve being persecuted by the government, aliens or superpowers
- involve body, may believe body is under external control
- can lead to aggression
What is disorganised speech
- result of abnormal thought processes
- may slip from one topic to another (derailment)
- speech may be very incoherent (word salad)
- diagnosed by DSM but not ICD
What is grossly disorganised or catatonic behaviour
- inability or lack of motivation to initiate or even complete a task
- can lead to problems of personal hygiene or be overactive
- catatonic refers to adopting rigid postures or aimless repetition of same behaviour
- diagnosed by DSM but not ICD
What are examples of negative symptoms
- speech poverty (alogia)
- avolition
- affective flattening
- anhedonia
What is speech poverty
- SZ characterised by changes in patterns of speech
- emphasis is on reduction in amount and quality of speech
- sometimes accompanied by delay in sufferer’s verbal responses during conversation
- may be reflected in less complex syntax
- appears associated with long illness and earlier onset of illness
What is avolition
- finding it difficult to begin or keep up goal directed activity
- SZ sufferers often have reduced motivation to carry out a range of activities
- Andreason (1982) identifies signs; poor hygiene and grooming, lack of persistence in work or education and lack of energy
What is affective flattening
- reduction in range and intensity of emotional expression
- SZ sufferers have fewer body and facial movements and smiles, and less co-verbal behaviour
- patients may show deficit in prosody (intonation, tempo, loudness and pausing) when speaking, giving cues to emotional content of conversation
What is anhedonia
- loss of interest or pleasure in all or most activity
- lack of reactivity to normally pleasurable stimuli
- physical anhedonia is inability to experience physical pleasures such as pleasure from food or bodily contact
- social anhedonia is inability to experience pleasure from interpersonal situations such as interacting with other people
What are issues associated with the classification and diagnosis of SZ
- reliability
- validity
- co-morbidity
- symptom overlap
- gender bias
- cultural bias
How is reliability an issue for the classification and diagnosis of SZ
- Whaley (2001) found interrater reliability between diagnosticians was as low as 0.11 using the DSM
- Cheniaux et al. (2009) also found low inter rater reliability
- had 2 psychiatrists independently diagnose 100 patients using ICD and DSM
- inter rater reliability was poor with one diagnosing 26 with DSM and 44 with ICD but other psychiatrist diagnosed 13 with DSM and 24 with ICD
How is validity an issue for the classification and diagnosis of SZ
- can be assessed using criterion validity (using different assessment systems to arrive at same diagnosis, e.g. DSM and ICD)
- SZ diagnosis more likely using ICD than DSM according to Cheniaux’s study, showing over diagnosis in ICD and under diagnosis in DSM
What studies have been carried out to test validity of SZ diagnosis and classification
- Rosenhan (1973)
- Birchwood and Jackson (2001)
- Osario (2019)
What studies have been carried out to test reliability of SZ diagnosis and classification
- Osario et al. (2019)
How did Osario et al. (2019) test reliability in SZ
- reported interrater reliability between pairs of psychiatrists was 0.97
- test-retest reliability was 0.92
- suggests most recent diagnosis of SZ using DSM is good and reliable
How did Rosenhan (1973) test validity in SZ
- 8 pseudo patients able to get admitted in psychiatric hospital using symptoms of hearing voices
- during stay, all patients behaved normally and showed no signs of mental illness
- found all 8 patients stayed for 7-52 days
- all but one patient discharged with SZ in remission
- shows diagnosis was poor
How did Birchwood and Jackson (2001) test validity in SZ
- found 20% of patients of SZ show complete recovery and never have another SZ episode
- 10% show significant improvement
- 30% show some improvement
- 40% never recover
- 10% affected and commit suicide
- great variation in prognosis suggests poor predictive validity
- however, Mason (1997) found use of newer classification has improve the predictive validity of diagnosis, particularly when the 6 month criteria for diagnosis was used rather than 1 month
How did Osario (2019) test validity in SZ
- suggests that because reliability is so high using DSM, validity would also be high using this single diagnostic system, suggested ICD needs more revision
How is co-morbidity an issue for the classification and diagnosis of SZ
- idea that 2+ mental disorders occur together
- if this is the case, we can question validity of diagnosis for SZ
- Buckley et al. (2009) concluded around half patients with SZ also have depression (50%), or substance abuse (47%)
- PTSD (29%) and OCD (23%) also occurred
- poses challenge as it shows we are unable to distinguish between disorders
- might mean severe depression looks like SZ, or vice versa
How is symptom overlap an issue for the classification and diagnosis of SZ
- means there is considerable overlap between symptoms of SZ and other conditions, such as depression and bipolar disorder
- Ellason and Ross (1995) point out people with DID having more SZ symptoms than people diagnosed with SZ
- most people diagnosed with SZ have sufficient symptoms of other disorders that they could also receive at least one other diagnosis (Read, 2004)
How is gender bias an issue for the classification and diagnosis of SZ
- Longenecker et al. (2010) reviewed SZ studies since 1980s, finding men more likely to be diagnosed
- may happen to be a gender bias in diagnosis as women seem to function better than men, having good family relationships and more likely to work (Cotton, 2009)
- therefore less likely to be diagnosed with SZ as women show better interpersonal function
How is cultural bias an issue for the classification and diagnosis of SZ
- African American and English people of Afro Caribbean origin are 9 times more likely to be diagnosed with SZ (Pinto and Jones, 2008)
- positive symptoms (auditory hallucinations) are acceptable in Africa because of cultural beliefs in communication with ancestor which are acceptable and not warranted to a diagnosis in Africa
- may be because Western cultures doubt honesty of black people (Escobar, 2012)
What are the advantage of classification and diagnosis of SZ
- communication shorthand; patient with mental disorder often has numerous symptoms. Simpler to incorporate these symptoms into a single diagnosis, making communication between mental health professionals easier
- treatment; often specific to certain disorders so a reliable diagnosis can point to a therapy that will alleviate symptoms
- although variation, there are many underlying biological abnormalities seen in people with SZ. It is hoped that a greater understanding will lead to more effective treatment
What are the two biological explanation factors of SZ
- genetic basis
- neural correlates
How can the genetic basis be tested
- family studies
- twin studies
- adoption studies
How are family studies used to investigate biological explanations of SZ
- find individuals who have SZ and determine whether biological relatives are similarly affected more often than non-biological relatives
- family studies show that the closer the genetic relatedness, the greater the risk to get SZ
Who has done research into family studies as a biological explanation of SZ
- Gottesman (1991)
What did Gottesman (1991) find when investigating family studies as a biological explanation of SZ
- 46% chance of SZ if both parents have it
- 13% chance of SZ if one parent has it
- 9% chance of SZ if a sibling has it
- shows the closer you are genetically related, the more likely you are to get SZ
How are twin studies used to investigate biological explanations of schizophrenia
- an opportunity for researchers to investigate nature/nurture debate in terms of contribution of heredity and environmental influences of SZ
- MZ twins share 100% of genes but DZ twins share 50% of genes
- concordance rate should be higher for MZ than DZ if SZ is genetic
Who has done research into twin studies as a biological explanation of SZ
- Gottesman (1991)
- Jospeh (2004)
What did Gottesman (1991) find when investigating twin studies as a biological explanation of SZ
- found 48% concordance rate for MZ twins
- 17% concordance rate for DZ twins
- shows the more genetically similar you are, the more likely you are to get SZ
What did Joseph (2004) find when investigating twin studies as a biological explanation of SZ
- did a review of twin studies that were carried out up to 2001
- found an overall concordance rate for MZ twins as 40% but 7.4% for DZ twins
- as concordance rate is still relatively high for MZ twins, his study supports idea of genes playing a big part in SZ
How are adoption studies used to investigate biological explanations of schizophrenia
- difficult to separate genetic from environmental influences in twin and family studies
- carried out to understand influence of nature/nurture
- adopts studies are researched to see nature/nurture influences when MZ twins may be reared apart of offspring from SZ parents are adopted
Who has done research into adoption studies as a biological explanation of SZ
- Tienari et al. (2001)
What did Tienari et al. (2001) find when investigating adoption studies as a biological explanation of SZ
- carried out study in Finland
- 164 adoptees who’s mothers had SZ, 11 (6.7%) also diagnosed with SZ compared to control group of 197 adoptees where only 4 (2%) were diagnosed with SZ
- shows although percentage of children adopted by non schizophrenic parents having SZ was low, there was a small link between genes and SZ with children whose biological mothers were schizophrenic
What are candidate genes in relation to SZ
- specific genes seemed to be associated with SZ
- now agreed SZ is polygenic => combination of different genes that have been implicated in SZ
Who has done research into candidate genes as a biological explanation of SZ
- Ripke et al (2014)
What did Ripke et al. (2014) find when investigating candidate genes as a biological explanation of SZ
- compared genetic makeup of 37k SZ patients worldwide with 113k controls
- found 108 separate genetic variations associated with increasing SZ
- the genes that were particularly vulnerable were the ones with connections to functioning of certain neurotransmitters, such as dopamine
What are examples of evaluation points for the genetic basis of SZ
- research supported
- nature nurture
- family history
- diathesis stress model
How does the genetic basis of SZ being research supported act as an evaluation point
- positive evaluation point
- lots of research evidence supporting genetic basis for SZ; Gottesman, Joseph and Tienari
- shows link between genes and SZ
- strength as it shows if a child grows up in a family where both biological parents have SZ, chances is heightened than if one or no parents have it
- shows genetics is an important factor
How is the nature nurture debate an example of an evaluation point for the genetic basis of SZ
- problem with twin and family studies is separating nature from nurture
- e.g. MZ twins are normally reared together making it difficult to separate upbringing frmo genes
- even when looking at adoption studies, children tend to be adopted by relatives who may still have similar rearing as biological parents
- adoption studies thus may not always be a good comparison for the effects of nature or nurture
How does family history act as an example of an evaluation point for the genetic basis of SZ
- SZ can take place in absence of a family history
- one explanation is a mutation in parental DNA, such as in paternal sperm cells
- can be caused by radiation, poison or infection
- evidence for role of mutation comes from Brown et al’s. 2002 study showing positive correlation between paternal age and increased risk of SZ increasing from around 0.7% with fathers under 25 to over 2% in fathers over 50
- suggests although genes are not directly involved, person can still get SZ if father was old at time of fertilisation
- suggests role of nature and nurture both play a part rather than just genes
How is the diathesis stress model an example of an evaluation point for the genetic basis of SZ
- states there is a genetic vulnerability in SZ
- vulnerability only likely to be triggered if there is a stress-trigger in the individual’s life
- an individual may be born with a gene which makes them particularly vulnerable to SZ but if life is stress free then they may not end up with disorder
- thus we need to be cautious when looking at genetic factors since they alone may not trigger SZ
What is neural correlates as a biological explanation for SZ
- measurements of the structure or function of the brain that have a relationship with SZ, especially different regions of the brain
- refers to how different neurotransmitters, such as dopamine and serotonin, in different parts of the brain can also play a part in SZ
What type of SZ symptoms have neural correlates
- both positive and negative symptoms
Who has done research into neural correlates of SZ
- Torrey (2002)
- Weinberger and Gallhofer (1997)
- Conrad et al. (1991)
How has Torrey (2002) researched into neural correlates of SZ
- using brain imaging techniques, researchers have discovered many SZs have enlarged ventricles, cavities in the brain that supply nutrients and remove waste
- ventricles of a person with SZ are 15% bigger than normal (Torrey, 2002)
- people with SZ with enlarged ventricles display more negative than positive symptoms
- these people also respond poorly to typical antipsychotics
- enlarged ventricles may be result of poor brain development or tissue damage, leading to development of SZ
How have Weinberger and Gallhofer (1997) researched into neural correlates of SZ
- prefrontal cortex (PFC) is main area of brain involved in executive control
- research shows this is impaired in SZ patients
How has Conrad et al. (1991) researched into neural correlates of SZ
- hippocampus is an area of brain in temporal lobe
- several studies have reported anatomical changes in hippocampus in SZ patients
- deficits in nerve connections between the hippocampus and prefrontal cortex have found to correlate with the degree of memory impairments in SZs
What are the strengths of neural correlates as a biological explanation of SZ
- evidence to support structural changes in brain between SZ and non SZ
- e.g. Torrey’s research with reference to enlarged brain ventricles and Conrad’s study with regards to the hippocampus - research evidence can be validated through brain scanning => objective
- shows face validity to the neural correlates explanation
- because one can observe structural brain changes occurring with SZ patients
- can help to tailor make treatments to reduce symptoms of SZ
What are the weaknesses of neural correlates as a biological explanation of SZ
- problem with looking at different brain regions is the fact that there are individual differences in sufferers of SZ
- not all patients have deficits in functioning of different brain regions - there are different brain regions involved in SZ
- may be difficult to pinpoint which brain region is causing symptoms - may be difficult to establish cause and effect in terms of neuroatomy
- evidence is correlational
What is an important aspect of the neural correlates aspect as a biological explanation for SZ
- dopamine hypothesis
What is the dopamine hypothesis
- claims an excess of the neurotransmitter dopamine in certain regions of the brain is associated with positive symptoms of SZ
- thus messages from neurons that transmit dopamine often lead to hallucinations and delusions
- SZs are thought to have high levels of D2 receptors on receiving neurons resulting in more dopamine binding and therefore more neurons firing
What are the two consequences of the dopamine hypothesis
- hyperdopaminergia
- hypodopaminergia
What is hyperdopaminergia
- based on original version of dopamine hypothesis in explanation SZ
- states there are high levels of dopamine in the subcortex
- e.g. excess of dopamine receptors in the Broca’s area may be associated with problems in speech and/or experience of auditory hallucinations