Schizophrenia P3 Flashcards
What is schizophrenia?
There is no single defining characteristic for schizophrenia, but it is a collection of symptoms that appear to be unrelated to each other.
= A severe mental disorder where contact with reality and insight are impaired, an example of psychosis.
What are the two major classification systems for SZ + their classification of symptoms?
DSM-5:
-> Requires one positive symptom to be present for diagnosis.
-> Symptoms must exist for at least 6 months for a diagnosis
-> Previous classification (DSM-4) included 5 subtypes, but all of these have now been removed.
ICD-10
-> Two or more negative symptoms to be present for diagnosis
-> Symptoms must exist for one month for a diagnosis
-> Contains 7 subtypes but the new ICD-11 has removed them
= The differences between classification systems questions the validity and reliability of classification and diagnosis of SZ.
The positive symptoms of SZ
Pos -> experiences additional to those of ordinary existence
1) Hallucinations
= Distorted perception of real stimuli.
- Can occur in any of the senses
- Most common as auditory hallucinations e.g. hearing a voice directing you to do smt/more than one voice in a convo.
2) Delusions
= Distorted/false beliefs that have no basis in reality.
- Paranoid delusions : such as persecutory beliefs that aliens or the government are trying to kill them.
- Delusions of Grandeur : whereby the individual believes they are someone of significant importance, such as a religious prophet, God, President etc.
What is meant by classification of a mental disorder?
= The process of organising symptoms into categories based on which symptoms frequently cluster together.
The negative symptoms of SZ
Neg -> involve the loss/reduction of usual abilities and experiences.
1) Speech poverty
= A reduction in the amount of quality of speech, with very brief replies and minimal elaboration.
- May include a delay in verbal responses during conversation.
2) Avolition
= Severe loss of motivation to carry out everyday tasks e.g. work hobbies and personal care, resulting in lowered activity levels.
- Sufferers have an inability to make decisions and lack sociability and affection.
Reliability in diagnosis and classification
= The consistency of the application of the classification and diagnosis symptoms when diagnosing SZ. (should produce same results/diagnosis).
1) Inter-rater reliability : Consistency across different psychiatrists diagnosing the same patient or set of symptoms.
2) Test-re-test reliability : Consistency of the patient’s diagnosis across time. If the same symptoms are presented again at a later point, the same diagnosis should be given.
Eval of Validity of classification of SZ
CON:
1) Subjective ( not possible to objectively test for SZ)
- Instead, clinicians must rely on symptoms reported by individual/family.
- This subjectivity can result in misdiagnosis, incorrect treatment and stigmatization, whereby being labelled as ‘SZ’ can have a long lasting, neg effect on social relationships, work prospects and self-esteem.
2) Contrasting evidence of the validity of class/diagnosis
- Rosenhan
-> 8 healthy individuals (5 men, 3 women), who presented at 12 diff psychiatric hospitals complaining of hearing indistinct voices saying “empty”, “hollow” + “thud”.
= 7/8 of them were diagnosed with SZ.
- Rosenhan told staff that more pseudo-patients would try to gain admittance (but none acc appeared).
- However, 41 genuine patients admitted-> 19/41 were suspected as being frauds by one psychiatrist and another member of staff.
= Therefore, it is clear that we cannot distinguish between the sane and insane in psychiatric hospitals. Shows the inability of clinicians to determine who does/doesn’t have a psychological condition like SZ, and also highlights subjectivity of diagnosis process.
3) Rosenhan’s study lacks temporal validity (1970)
-> Therefore the knowledge of SZ has improved greatly + the process and systems of classification/diagnosis, meaning they have been developed and revised since then.
-> Therefore, likely if this research were to be replicated, the same findings would not occur!!
Eval of Reliability of classification of SZ
PRO:
1) Reliability means that info and research findings can be shared
- May lead to a greater understanding of its causes + lead to more effective treatments.
- In general, as classification systems have been updated, there is evidence that reliability of diagnosis has improved over time.
- Therefore, although there have been issues, it is still valuable to have that systems in terms of helping patients achieve a diagnosis and so treatment can be prescribe which may improve their quality of life. ( also lowers taboo, takes away mystery of mental illness)
CON:
1) Low reliability in inter-rater and test-retest
a) Cheniaux et al
- 2 psychiatrists, independently diagnosed 100 patients using DSM + ICD.
- one found: using DSM 26 had SZ and using ICD 44 had SZ
- other found: using DSM 13 had SZ and using ICD 24 had SZ
= consequence of an incorrect diagnosis means patient doesn’t get correct treatment and so may be a threat to themselves or others.
b) Read
= Found test-retest reliability rates of 37% in diagnosis of SZ.
Validity in diagnosis and classification
= How accurate diagnosis is.
1) Descriptive validity : Agreement across psychiatrists on what SZ is and who has it.
- if same symptoms should be given same diagnosis
2) Predictive validity: Patients should respond similarly to treatments, and the clinician should be able to make accurate predictions on patients prognosis.
3) Aetiological validity: The disorder should have the same underlying cause.
Issues which affect the reliability and validity of diagnosis
symptom overlap
comorbidity
culture bias
gender bias
Symptom overlap (as an issue which affect the reliability and validity of diagnosis)
= when the same symptoms of one disorder are prevalent in another
-> symptoms of SZ are not exclusive to SZ
-> eg bipolar + SZ = avolition and delusions
-> occurs BEFORE diagnosis is given and can lead to comorbidity
RELIABILITY:
-> Psychiatrists have lower inter-rater and test-retest reliability due to…
1) subjective nature of clinicians opinions + patients and family reports.
2) differences in symptoms required for DSM5 and ICD10.
= therefore, becomes more difficult for psychiatrists to consistently agree on a diagnosis.
VALIDITY:
Low descriptive validity…
-> Ophoff -> Assessed genetic material and found 7 gene locations on genomes associated with SZ (3 of which were also associated with bipolar).
= Therefore questions usefulness of classification systems if misdiagnosis is probable. (eg do psychiatrists rlly know what SZ is? Are bipolar/SZ the same disorder?).
IMPLICATIONS/CONSEQUENCES:
-> Misdiagnosis: inappropriate treatment meaning the individual does not experience relief from symptoms.
-> Can exacerbate condition or expose them to side effects of the drugs which they need not experience.
Comorbidity (as an issue which affect the reliability and validity of diagnosis)
= when a patient suffering from one disorder (eg SZ) is simultaneously suffering from an additional disorder (eg depression/ substance abuse)
-> Occurs AFTER diagnosis
-> Clinicians must make a dual diagnosis
RELIABILITY:
-> Low test retest as it is hard to consistently allocate symptoms of each condition to appropriate disorder.
-> Buckley : 50% SZ = also had depression
47% SZ = also had substance abuse
= These high rates have comorbidity complicate diagnosis and decrease the likelihood of clinicians agreeing.
VALIDITY:
-> Misdiagnosis can occur due to misinterpretation of symptoms. For example if you have avolition it may be depression or SZ.
= Therefore, if a patient has both it is difficult to know which disorder the symptom belongs to.
IMPLICATIONS/CONSEQUENCES:
-> Sim : 142 hospitalized patients, 32% = comorbidity
HOWEVER, only patients selected had exclusively SZ only.
= Therefore, by excluding comorbid patients from research, lack of understanding -> more research is needed.
Culture bias (as an issue which affect the reliability and validity of diagnosis)
= People from different backgrounds (not western) are more likely to receive a diagnosis of SZ , as it is abnormal to that clinicians culture.
->Rates of SZ worldwide are relatively consistent (1%).
-> psychiatrists in western cultures tend to be from middle / upper class with white backgrounds.
-> When there is a MISMATCH between cultural backgrounds of patient and clinician there are different social norms for what is considered abnormal (eg voices)
RELIABILITY:
Different culture norms leads to inconsistent diagnosis…
-> Keith : 2.1% african americans w/SZ compared to 1.4% of white americans.
-> So…Maybe we need different C&D Systems for different cultures instead of generalizing ideal mental health in western cultures. // match patient and psychiatrist culturally to increase rel
VALIDITY:
-> Invalid diagnosis when psychiatrists carry out cross cultural assessments.
-> Escobar : White psychiatrist tend to over interpret symptoms of black patients + don’t trust their honesty
-> Psychiatrist subjective bias can lead to misinterpretation as SZ symptoms differ in different cultural norms.
= Therefore, improve training given to psychiatrists and more cross cultural assessments.
IMPLICATIONS/CONSEQUENCES:
-> Misdiagnosis may skew the knowledge and understanding of condition.
-> Prevalence rates in certain ethnic groups may appear higher when not. Which leads to stigmas which may have a negative economical impact (lack of employment) or social (isolation).
= Therefore, may be prescribed wrong antipsychotics negative impact on quality of life.
Gender bias (as an issue which affect the reliability and validity of diagnosis)
= Male mental health argued to be a benchmark for assessment, causing gender bias in the application of C&D Systems when assessing females.
-> Longnecker: males more likely to have SZ than females, so more likely to be diagnosed.
-> Males have an earlier onset than females
-> Males tend to suffer from negative symptoms
RELIABILITY:
Low inter rater reliability…
-> Loring + Powell : 290 psychiatrist to assess two patients (same symptoms)
Male: 56% SZ
Female: 20% SZ
= Therefore, Subjectivity of psychiatrists that males are more likely to have SZ alters diagnosis.
VALIDITY:
-> Cotton: females more likely to carry on working / be more social than men when having SZ.
-> Due to different coping mechanisms…
males: social withdrawal
females: seek support
= Therefore, undermining difference between genders, so male Ben h mark for assessment is invalid when classifying and diagnosing female symptoms of SZ
IMPLICIATION/CONSEQUENCES:
-> An underdiagnosis of females means that they may not receive the help they need.
-> males overdiagnosis means treatment given when not needed which may cause harm.
= Therefore, better training for psychiatrists and how male and female will present in a clinical setting when reporting symptoms of SZ
What are the biological explanations of SZ?
-> Genetic factors
-> Neural correlates (dopamine hypothesis/ ventricles)
Biological explanation: Genetic Factors
= SZ may be an inherited condition as it seems to run in families.
-> family studies; The closer the degree of genetic relatedness between sufferers, the greater the risk of developing a disorder.
-> EG -> child with two SZ parents = 46%
child with one SZ parent = 13%
child with SZ sibling = 9%
-> Kender et al : Found first degree relatives 18 times more likely to develop SZ than population.
-> Candidate genes: Associated with greater risk inheritance.
SZ is…
a) polygenic condition = Requires a combination of different genes in order to predispose individual> one gene.
b) aetiologically heterogenous = Different combinations of factors can lead to SZ.
Evaluation of genetic factors (bio exp of SZ)
PROS:
1) Janicak et al
MZ: 48% concordance rates
DZ: 17% concordance rates
-> SZ has a genetic basis.
2) Tiernari et al
= Studied finish adoptees whose biological mothers had been diagnosed with SZ.
-> 6.7% = also received SZ diagnosis> 2% control
= therefore cover increased genetic risk in those who have first degree relatives (sz is nature>nurture).
NEGS:
1) Reductionist
= Families share the same environment therefore can be difficult to assess how much of the effect is down to nature or natural.
-> Twin studies do not show rates of 100% concordance rates amongst MZ twins therefore genetic explanations can be considered too reductionist as they do not account for other factors such as situational or cognitive.
-> Instead, an interaction list approach should be used such as the interaction between a genetic predisposition and environmental triggers for the onset of SZ.
Evaluation of neural correlates as a bio exp for SZ
POS:
Evidence of hyperdopaminergia in subcortical regions…
1) Falkai et al
= Post mortems of SZ patients finding there was an increased dopamine concentration in left amygdala (subcortex) .
2) Wong et al
= PET scans showed greater dopamine receptor intensity in the Caudate nucleusin SZ>control.
3) Practical application
= Antipsychotic drugs Developed by reducing dopaminergic activity in the brain to decrease positive symptoms.
-> increases wellbeing of SZ + credibility of hypothesis
Cons
NEGS:
1) Reductionist
= Produces a complex disorder down to singular brain chemical (dopamine) or the structure (enlarged ventricles), ignoring other important environmental social influence, such as family dynamics.
-> Therefore a more interactionist approach needed.
2) Cause and effect
= Researchers conducted retrospectively on individuals who already had SZ who were likely to have been treated.
-> Is no comparison of neural transmitter levels before the development of SZ
-> It could be that having SZ could have altered the dopamine activity and therefore led to the high levels of dopamine activity observed> rather than the abnormal doping activity being the cause of the disorder.
