Schizophrenia Flashcards
There are two widely used classification systems in psychiatry in defining and classifying mental disorders. What are they?
ICD (international classification for disease) - produced by world health organisations. On its 10th edition, 11th to come out in 2015. Mental disorders weren’t included until 1952 but now 1 out of 21 chapters is devoted to MD, published separately.
DSM (diagnostic and statistical manual of mental disorders) - produced by American psychiatric association. In the US research on disorders has to use DSM.
What is psychopathology?
The study of mental disorders and their origins.
The classification and diagnosis of mental disorders is important.
What does a) classification mean?
b) diagnosis mean?
a) the act of distributing things into classes or categories of the same type
b) identification of disease by its signs and symptoms
The multi-axial system in DSM IV has been dropped from DSM - 5. Why do you think the DSM has been continuously revised?
- Increase reliability
- New treatments and illnesses
- Social development eg homosexuality
Broadly speaking, what is schizophrenia?
Severe disruption in psychological functioning, referred to as psychosis. It is defined by abnormalities in one or more of the following five domains: delusions, hallucinations, disorganised thinking, abnormal motor behaviour and negative symptoms.
Onset is between the ages..
…15-45. Usually occurs 4-5 years earlier in males
When are delusions deemed bizarre?
If they are implausible and not understandable to same culture peers. An example is that an outside force has removed their organs and replaced them without leaving any scars. A no bizarre illusion is the belief that one is under surveillance by police. The distinction between a delusion and a strongly held idea is sometimes difficult to make and depends in part on the degree of conviction with which the belief is held despite clear or reasonable contradictory evidence.
Symptoms.... Delusions? Hallucinations? Disorganised thinking? Catatonic behaviour? Negative symptoms?
- Delusions: fixed false beliefs, resistant to change in the light of contrary evidence including delusions of persecution, thought withdrawal. Their content may include a variety of themes e.g. Persecutory delusions (i.e. belief that one is going to be harmed, harassed by an individual or organisation) are most common. Referential delusions (i.e. belief that certain gestures, comments, environmental cues are directed at oneself) are also common as well as Grandiose delusions i.e. when an individual believes he or she has exceptional beliefs like wealth and fame,
- Hallucinations: perception like experiences without external stimulus. They are vivid and clear with the full force and impact of normal perceptions and not under voluntary control. They may occur in any sensory modality. Auditory hallucinations are usually experienced as voices that are perceived as distinct from the individuals own thoughts.
- Disorganised thinking: disorganised thought inferred from speech that is irrelevant and incoherent. The individual may switch from one topic to another. Answers to questions may be obliquely related or completely unrelated. Because middy disorganised speech is common and non-specific, the symptoms must be severe enough to substantially impair effective communication.
- Catatonic behaviour: is a marked decrease in reactivity to the environment. This ranged from resistance to instructions; to maintaining a rigid, inappropriate or bizarre posture; to complete lack of verbal and motor responses.
- Negative symptoms: account for a substantial portion of the morbidity associated with schizophrenia but are less prominent in other psychotic disorders. Two negative symptoms that are common are: diminished emotional expression - reduction in eye contact facial expressions and hand movements. Avolition - decrease in motivated self initiated purposeful activities.
What does reliability in the diagnostic sense mean?
The same diagnosis should be made by two or more clinicians ( inter rater reliability )
There is no universal agreement on how to define and diagnose schizophrenia but there is now greater agreement than in the past.
What’s the difference in type 1 and 2 symptoms?
ICD - 10 distinguishes between ? subtypes
DSM-IV distinguishes between ? subtypes
HOWEVER…
Type 1 - characterised by positive symptoms - behaviours and experiences that healthy individuals don’t experience.
Type 2 - characterised by negative symptoms - not showing behaviours that healthy individuals normally show
7
5
DSM 5 has dropped the subtypes and ICD 11 will drop them too because trials have shown that there is a lack of reliability in diagnosis of the sub-types.
What are 3 factors affecting reliability of diagnosis?
- Differences in procedures eg use of classification systems. If clinicians use different CS they are likely to make different diagnosis DSM is the dominant manual for diagnosis in the US while a mixture of diagnostic systems are used in the rest of the world. In the past this was a severe problem as doctors in different societies used very different diagnostic criteria….
COOPER 1972 - the psychiatric’s in New York diagnosed schiz twice as often as whilst London psychiatrists diagnosed mania and depression twice as often.
ICD allows diagnosis with symptoms only within the last month, while DSM insists on some symptoms in the preceding six months. CHENIAUX - rates of diagnosis schiz using ICD were higher than when using DSM 5. He traced this back to there being no need for symptoms in the last 6 months in ICD. - Differences in clinicians - clinicians may interpret the same classification system differently, even if the same classification system is being used. They each have a subjective interpretation Many phrases are open to interpretation. e.g. in DSM 5, delusions are deemed as bizarre is ‘ they are clearly implausible and not understandable to same- culture peers and do not derive from ordinary life experiences. MOJTABI & NICHOLSON - weak inter rater reliability between clinicians in judgments of whether hallucinations were bizarre or not. This suggest that different doctors interpret the criteria differently.
- Differences in patients - patients may present themselves differently on different days depending on mood and variability of symptoms. Patients may also react differently to certain doctors
The more reliable a diagnosis the more likely it is correct. However why is reliability not a guarantee of correctness?
Doctors could be reliably wrong! They could both make an incorrect diagnosis… Illustrated by Rosenhan’s study in which pseudo- patients reported that they were hearing a voice saying thud to doctors at a psychiatric hospital. All but 1 were diagnosed with schizophrenia. In this case doctors were very reliable but invalid.
Validity of diagnosis A01
A valid diagnosis is one that is correct. In order for diagnoses to be correct 2 main conditions have to be satisfied - what are they?
1) How does reliability relate to validity of diagnosis?
2) Why is there a major problem with validity of schizophrenia
3) How does validity of classification relate to validity of diagnosis?
1) The illness has to be reliability defined/ classified and diagnosed.
2) The illness has to be validly defined or classified.
1) If the reliability of diagnosis is poor then so too is the validity. If there is inconsistency in diagnosing schizophrenia across two or more clinicians then at least one must be an incorrect diagnosis. The more reliable the diagnosis, the more likely the correct diagnosis is being made. However reliability is not a guarantee of correctness (validity). Doctors could be reliably wrong! As seen with Rosenhans study in which pseudo-patients repotted that they were hearing a voice saying ‘thud’ to doctors at psychiatric hospitals and all but one received a diagnosis of schizophrenia. In this case, the doctors were very reliable in their diagnosis but they were invalid.
2) What can be observed is an indirect sign of the illness. In schizophrenia, there is no physiological indicator of the illness. No indicator, no lab test, that objectively settles whether someone has schizophrenia. Psychiatrists can only observe behaviour and talk to patients. This makes genuine verification of the validity of a diagnosis very difficult.
3) S has been one of the most fiercely debated disorders. The lack of consistency in definition of the illness again shows that there is a problem of validity; if people disagree about what the illness is then they cannot all be correct. For diagnosis to be valid we need to be confident that doctors are not just consistent but right; in absence of a definitive physiological marker for the illness, we need to be confident that S has been classified in a valid way and this is assessed in three ways…
1) Descriptive validity - are the symptoms right? It is usually possible to define medical illnesses by their symptoms which distinguishes them from other conditions.
2) Aetiological validity - can we identify causes/mechanisms? It is plausible to use evidence from causes or mechanisms to argue that an illness is well-defined.
3) Predictive validity - what is the prognosis/reaction to treatment? we should be able to define how the illness progresses over time and predict how they will react to treatments.
Evaluation and Evidence relating to descriptive validity of schizophrenia?
Why has Aetiological validity also been questioned?
Schizophrenia lacks descriptive validty. Patients with very different symptoms can all be diagnosed with s e.g. positive symptoms differ from negative ones. It could be argues that the diversity of symptoms in s show that it is a vague label for a set of independent symptoms ( BENTALL). It might be better to explain and treat independent symptoms rather than claim there is a single illness called S.
On way to investigate descriptive validity is cluster analysis- if you have one symptom of schizophrenia you should be more likely than the average person to have one or more of the others
A02 -Evaluation Validity
1) While explanations of causality differ to some extent, research shows that genetic vulnerability is involved in all types of schizophrenia. What research showed this?
2) Invalid diagnosis also have serious implications for treatment. If diagnoses are invalid two errors can occur. What are they?
1) - Significantly higher concordance rates in mz than dz twins has been reliably shown - This to some extent answers criticisms over aetiological vulnerability however type 1 S appears to be caused by a dopamine imbalance. This evidence once again suggests that the classification of s as a single illness is problematic.
Liddle supports doubts raised over descriptive validity found 3 clusters of symptoms, positive, negative, and symptoms of cognitive disorganisation. This suggests that the classification of schizophrenia as single illness is problematic and distinctions within it are needed.
2) One is a false positive - In this case a patient is diagnosed dwith an illness that they do not have and may then be treated with powerful drugs which may harm them. This is shown in SWARTZ case study of an African American woman who was wrongly prescribed antipsychotics for 10 years to treat hallucinations and agitation. An EEG later revealed evidence of epilepsy, and when the appropriate treatment was given her treatment disappeared. In addition, the label ‘schizophrenia’ might become part of the persons identity. They might accept this label and in a self-fulfilling prophecy, develop symptoms of illness or deteriorate in functioning. The doctors may also reinforce the illness. Is is supported by Rosenhan - The patients making notes whilst on the ward was interpreted as ‘writing behaviour’ as if this was abnormal. Arriving early for lunch was interpreted as an ‘oral-inquisitive’ symptom.
- The other error is a false negative - if a patent is left undiagnosed with an illness they have then they will fail to receive the necessary treatment
Identify evidence suggesting schizophrenia has good aetiological validity?
Identify and explain evidence raising doubts of aetiological validity?
Clustered positive symptoms - caused by dopamine levels and deterioration in brain tissue explains negative symptoms
Classification of schizophrenia as a single illness is problematic and distinctions are needed
What is meant by the term labelling in relation to the diagnosis of schizophrenia? What evidence is there supporting negative effects of labelling?
When the word ‘schizophrenic’ becomes part of someone’s identity. Leads to self for filling prophecy and reinforcement of the illness.
Doctors interpret any behaviour as schizophrenia.. Rosenhan found that when patients were writing down observations or early for lunch they were seen by the psychiatric’s as excessive writing
Essay for THE RELIABILITY AND VALIDITY OF THE CLASSIFICATION AND DIAGNOSIS OF SCHIZOPHRENIA. (8 +16)
Discuss issues with the validity and/or reliability of the classification and diagnosis of Schizophrenia. (8+16)
A01: Reliability, in the diagnostic sense, is the consistency and sameness of a measure or method; it is important issue when classifying things. Classification is the act of putting things into categories, e.g. listing disorders with their symptoms. This is done for Schizophrenia and its symptoms in attempt to a create consistent classification of the illness however, sz is classified differently in different diagnosis tools such as the DSM and the ICD which means reliability becomes an issue. DSM is produced by the American psychiatric association and is most prominently used in America whilst ICD is produced by the world health organisations, used elsewhere. Different requirements are needed in the two different manuals before schizophrenia is diagnosed and therefore a patient may be diagnosed differently depending on what manual the clinician is referring to. Using the different classification systems mean that diagnosis of schizophrenia could be unreliable or inconsistent.
AO2: This was illustrated by Cooper 1972 who showed the same clinical videotape of an interview with a patient to clinicians in the US and the UK and found that in the US, clinicians diagnosed schizophrenia twice as often whilst in the UK, clinicians diagnosed depression and mania twice as often. This happened because they both used different classification systems, demonstrating that the use of different classification tools can lead to an inconsistency in diagnosis
A01: Problems with reliability in classification can still be evident if the same tool is used. Some sections of the same text can be subjectively interpreted as parts of the classification are not effectively operationalized. Many phrases are open to interpretation; in DSM 5, delusions are deemed as bizarre is ‘ they are clearly implausible and not understandable to same- cultured peers and do not derive from ordinary life experiences. The phrase is open for interpretation and therefore different psychologists may reach different conclusions from the same text, leading to low inter-rater reliability in the diagnosis of schizophrenia.
A02: Motjabi and Nicholson found weak inter rater reliability between clinicians in judgments of whether hallucinations were bizarre or not when using DSM 4, illustrating that Schizophrenia is not sufficiently defined to achieve reliable diagnosis and suggests that different doctors interpret the criteria differently.
A03: However, classification systems are constantly being revised and updated in order to improve reliability in diagnosis. For example DSM 5 has dropped subtypes of schizophrenia and ICD 11 will drop them this year since trials have shown that there is a lack of reliability in diagnosis of the subtypes. Despite this, research has shown that other disorders have significantly more consistency in diagnosis and there is generally more agreement between clinicians over diagnosis of for example autism and PTSD. If other psychological illnesses can be reliably and validly defined, then schizophrenia should be also.
A01: Validity is the accuracy and truth of measurement or diagnosis. There are issues in the validity of diagnosis of SZ because reliable classification is a precondition for valid diagnosis. If there is inconsistency in diagnosing schizophrenia across two or more clinicians then at least one must be an incorrect diagnosis. Nevertheless, a reliable diagnosis may still be an invalid diagnosis because clinicians may all reach the wrong conclusion and therefore be reliably wrong. This was demonstrated by
A02: Rosenhan who sent 13 students to different clinics, asking each to claim they could repeatedly hear the word ‘thud.’ All but one were diagnosed with SZ and this illustrates how clinicians can similarly make the wrong diagnosis.
A01: Many psychologists have suggested that it is perhaps not entirely appropriate to define SZ as a single overall disorder due to its diverse nature of symptoms. There is therefore many issues with descriptive validity. This is the extent to which classification tools accurately define the symptoms of SZ however individual patients who have been diagnosed with illness may have very little in common with each other; symptoms differ immensely so that some people may have auditory hallucinations whilst others may show catatonic behaviour.
A02: Bentall suggest that Schizophrenia is too wide a label for the set of independent symptoms and that we should split the illness into three groups; positive symptoms, negative symptoms and cognitive disorder. Doing this, would allow a more specific diagnosis and more appropriate to each indivudal patient. This system would also improve aetiological validity (the causes and mechanisms of the illness) and allow for more accurate and specific diagnosis and more appropriate subsequent treatment which would consequently improve predictive validity (prognosis and reaction to the treatment).
Despite being updated and improved, the descriptive validity of SZ is still rather low meaning that classification systems are not fully valid.
A01/ A02:The main issue with an invalid diagnosis is that the clinician may make a false positive diagnosis. This is when a patient is not diagnosed with an illness they in-fact have and consequently the patient will receive the wrong, or no, treatment. Such an issue was illustrated by Schwarz who demonstrated that invalid classification can lead to invalid diagnosis in a case study of an African American lady who was diagnosed with SZ after experiencing auditory and visual hallucinations. She was treated for 10 years with antipsychotic drugs but clinicians later discovered that she in fact suffered from epilepsy. The fact that some of her symptoms were alleviated by antipsychotics reinforced the invalid diagnosis but meant that appropriate treatment was withheld for a long time and she had to experience the negative side effects of the drug. This case study highlights the problem with invalid diagnosis; if SZ was validly diagnosed, such false positive diagnosis would be less likely. A false positive diagnosis can also become an issue when the individual is labelled a ‘schizophrenic’ or ‘mentally ill,’ leading to the ‘self-fulfilling prophecy. The patient may believe themselves that they have the illness and embody the symptoms after being falsely diagnosed. This may lead to the development of the illness when it would not otherwise occur and highlights another issue of invalid diagnosis.
A false negative diagnosis is when a patient is not diagnosed with schizophrenia, when they in-fact have the disease. This means that treatment is withheld and not given so the individual does not get better and suffers despite available treatment.
Overall, there are many ethical implications for both a false negative and a false positive diagnosis so therefore it is not only advantageous but also very important to get the diagnosis correct and to do this there must be valid definition of the disorder.
