Schizophrenia Flashcards
(24 cards)
What are the two main systems for classification of schizophrenia ?
the DSM 5 - American
the ICD 11 - world health organisations classification
Define positive symptoms of SZ. What two types plus two additional bonus positive symptoms?
They are additional experiences beyond those of ordinary existence.
1)Hallucinations - unusual sensory experiences. Some are related to the environment, some bear no relationship
2) Delusions - irrational beliefs that are resistant to confrontation of the truth.
3) Psychomotor disturbances: rocking back and forth etc
4)Catatonia - staying in position for hours/days
What forms of delusions can people with SZ get?
1)Delusions of persecution: the belief that others want to harm, threaten or manipulate you
2)Delusions of grandeur: the idea that you are an important individual, even God-like and have extraordinary powers. One of the most common types of this delusions is the belief that they are Jesus
3)Delusions of control: may belief that they are under the control of an alien force that has invaded their mind and/or body.
Define negative symptoms. What are the two types of negative symptoms?
They involve the loss of usual abilities and experiences.
1) Avolition (apathy): finding it difficult to begin or keep up with goal-direct activities. Sufferers of SZ often have reduced motivation to carry out a range of activities
2) Speech poverty (agolia): changing patterns in speech, this is because of the reduction in the amount and quality of speech in SZ. This can be manifested as a delay in the sufferers’ responses during conversations.
(Andreason 1982) What are the three signs of avolition?
1) Poor hygiene and grooming
2) Lack of persistence in work or education
3) Lack of energy
What does reliability mean?
Means there is good consistency over time between the individuals (the raters) who are using the system to rate patients. If two therapists often disagree in their diagnosis of patients then this would suggest a low reliability for that system.
What does validity mean?
Means that the diagnostic system assesses what it claims to be assessing. In the case of SZ, it means that patients who are diagnosed as sufferers of SZ do actually have that mental disorder.
Essay plan for discuss the reliability and/or validity in relation to the diagnosis and classification of schizophrenia (8 marks)
A01:
-outline validity and reliability in relation to SZ
-How co-morbidity and symptom overlap can impact the reliability and validity
A03:
(-)lack of validity - Rosenhan - what did he do? what did he find? +low pop validity
(-)Lack of reliability - Cheniaux - what did he find?
(-)Lack of reliability Rosenhan
8 confederate pseudopatients to 12 diff hospitals. Complained of hearing voices saying “empty”, “hollow” and “thud”. Once on the ward stopped pretending symptoms and behaved normally. Staff diagnosed 11 pseudopateints with sz and one with manic-depression, staff never detected their sanity. The behaviour of pseudopateints being misinterpreted by staff puts into question the validity of the measure (ICD/DMS) for SZ and that the staff are not comfortable using the diagnostic tools due to symptom overlap. The validity of the diagnosis is weather the diagnosis is correct and leads to successful treatment and thus there is an argument for validity.
(-)Lack of reliability - Cheniaux
There is evidence to suggest that the inter-rater reliability(IRR) in the diagnosis of SZ is poor. For example, Cheniaux (2009) asked 2 psychiatrists to independently diagnose 100 patients using both DSM and ICD criteria. IRR was poor, with one psychiatrist diagnosing 26 with SZ according to DSM and 44 according to ICD, and the other diagnosing 13 according to DSM and 24 according to ICD. This inconsistency between MH professionals indicates poor reliability in the diagnosis of SZ because diff professionals are not arriving at the same diagnosis for each patient.
2 further evauation points about the diagnosis of scizophrenia other than lack of valididty and lack of reliability
(-)symptom overlap
(-)co-morbidity
Define Schizophrenia
Is a very serious condition. It translates to ‘split mind’ but is NOT the same as split personality disorder. It affects around 1% of the population and the symptoms exhibited vary considerably. Onset usually occurs mid to late adolescents, but it does range through to early adulthood. It is more common in men than women and are more commonly diagnosed in cities than countryside. The symptoms of SZ can interfere severely with everyday tasks, so that many sufferers end up homeless or hospitalised.
The diagnosis of SZ A03
(-)co-morbidity
There is research evidence to suggest that many patients with SZ often have other illnesses. This is co-morbidity . For example, in a review, Buckley et at al (2009) concluded that around half of the patients with a diagnosis of SZ have a diagnosis of depression (50%) or substance abuse (47%). Post-traumatic stress disorder also occurs in 29% of SZ cases and OCD in 23% of cases. This is a problem because it suggests that diagnostic tools cannot tell the difference between SZ and depression. In terms of classification it may be that very severe depression looks like SZ and vice versa and may benefit from being seen as a single condition. This further presents a problem in terms of the reliability and validity of diagnosis.
The diagnosis of SZ A03
(-)Symptom overlap (when there is considerable overlap between the symptoms of SZ and other conditions)
For example, both SZ 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 SZ. Under ICD a person may be diagnosed as Schizophrenic. However, many of the same patients would receive a diagnosis of bipolar disorder according to the DSM criteria. This is unsurprising given the overlap of symptoms, it even suggests that SZ and bipolar disorder may not be two different conditions but one.
What three factors form the biological explanation of SZ?
1)Genetic
2)Neuro-chemical factors (dopamine)
3)The function or structure of the brain (neural correlates)
The biological explanation of SZ (genetics) A01
-Twin studies
Based on the premise that it is an inherited disorder that runs in families; faulty genes are passed on from generation to generation.
1)Twin studies: Gottesman summarised the findings of 40 twin studies and found a concordance rate of 48% for MZ twins compared with only 17% for DZ twins. This shows that is MZ twins are more concordant than DZ twins then this suggests that the greater similarity is due to genetics
The biological explanation of SZ (genetics) A01
-Family studies
Gottesman found that if both parents had SZ, there was a 46% chance of developing the disorder, a 16% chance if one parent had it and a 1% chance if there are no relatives with it. A higher concordance rate with children with two parents with SZ than just one, suggests that the concordance rate is due to genetics. Similar as having no parents with SZ is only a 1% chance of developing the disorder.
The biological explanation of SZ (genetics) A01
-Adoption studies
Tiernari studied 112 adopted children who had been separated from their SZ mothers, and compared with 135 adopted children who did not have SZ mothers. He found that by the time they reached adulthood, 10.3% of those with SZ mother had developed the disorder compared to just 1.1% of those without. This shows that the SZ ‘genes’ still impacted the children’s behaviour, despite being in a different environment. Suggests there is a genetic element to SZ.
The biological explanation of SZ (genetics) A01
-Candidate genes explanation (not findings)
These are genes associated with the risk of inheritance. SZ is polygenetic, it requires a number of factors to work in combination not just one specific gene. As different studies have identified different candidate genes it would suggest that SZ is aetiologically heterogenous, different combinations of factors can lead to the condition.
The biological explanation of SZ (genetics) A01
-Candidate genes FINDINGS
Ripke et al combined all previous data from genome wide studies of SZ. They found that the make up of 37,000 patients compared to that of 113,000 controls; 108 separate genetic variations were associated with increased risk of SZ. Genes associated with the increased risk included coding for the functioning of a number of neurotransmitters including dopamine. This shows that there is no one gene that causes SZ, there are multiple genes that may have an influence. This could explain why there are so many different types of SZ e.g. paranoid SZ, catatonic SZ, residual SZ etc.
The biological explanation of SZ (Dopamine) A01
The brains chemical messengers appear to work differently in the brain of a patient with SZ. In particular dopamine (DA).DA is important in the functioning of several brain systems that may be implicated in the symptoms of SZ
The biological explanation of SZ (Dopamine) A01
-Hyperdopaminergia******
High levels of dopamine in the subcortex. For example, an excess of dopamine receptors in Brocas area (which is responsible for speech production) may be associated with poverty of speech and/or experience of auditory hallucinations.
The biological explanation of SZ (Dopamine) A01
-Hypodopaminergia *********
Goldman-Rakic et al have identified a role for low levels of dopamine in the prefrontal cortex (responsible for decision making) in the negative symptoms of SZ. It may be that both hyper and hypodopaminergia are correct explanations.
The biological explanation of SZ (Neural correlates) A01
Size/functions of various brain structures has been found to be linked to SZ and/or to specific symptoms of the disorder e.g. enlarged ventricles , reduced grey matter density and activity of the basal ganglia.
