Tuesday, 30 June 2015

Diagnosis, uncertainty and the hub of clinical decision making

Is diagnosis an authoritative statement about a patient’s condition? Does it involve 100% certainty that this is the correct label for the type of the patient’s problems, what the underlying causes are for the problems, that this is the sole problem, what the correct treatment should be, what the outcome is going to be with and without treatment?


In fact a doctor’s diagnosis is a summary of a series of possibilities that trigger further enquiries, not least is the diagnosis correct and should it be changed. These possibilities inform the doctor’s management plan such as what types of further tests and examinations the healthcare team should do and when.  What are these possibilities?

  • What kind of features does this diagnosis present with? The range of probabilities of how the diagnosis will present in terms of symptoms, signs, lab tests or other important clinical features. This will tell the doctor how to recognise the condition, what information to seek and how. It will guide the doctor in what questions to ask, how to interpret the answers, what tests to run and what pattern of results to look for. As noted elsewhere this is a pattern recognition exercise.
  • What if the diagnosis is wrong? The possibility that the diagnosis is correct (or its’ reliability) according to some external criteria – usually for most medical specialties, a test (such as biochemical test, pathology of diseased organ, imaging test) but could also be another expert doctor’s opinion. This possibility of the diagnosis made being incorrect means the doctor should continue to be vigilant for disconfirmatory information i.e. information that suggests the diagnosis is incorrect. This may be symptoms or signs or laboratory tests or not responding to a treatment that usually works or other differences in the clinical picture that are usually incompatible with the diagnosis or better explained by another diagnosis. If these arise then the doctor should revise (change) the diagnosis to one that fits the information better. The doctor keeps a differential diagnosis (or many differential diagnoses, or even the “null option” of no diagnosis/ no illness) in mind. For example, a patient with initial diagnosis of alcohol intoxication but then the doctor notices they have signs of a subarachnoid haemorrhage and changes the diagnosis to that instead.
  • What other illnesses could be present? The possibility that other healthcare problems are also present, known as co morbidity. Like birds of a feather, some illnesses are associated with other illnesses being present. An illness may increase the chances of developing another illness . Illnesses have similar underlying causes thus increasingly the probability of more than one illness. This alerts the doctor to look for signs or symptoms or run tests or investigations for these other potential diagnoses. For example if a patient has an unusual infection diagnosed such as pneumocystis carinii pneumonia this makes the doctor think that the patient may have an immunocompromised state (immune system that is very poor at fighting infections) so will run tests looking for causes of this such as HIV infection as well as taking precautions to reduce the chances of other infections.
  • What complications should I look out for? Apart from what the doctor has recognized and identified there can be other problems or features known to be associated with the diagnosis. This triggers the doctor to look for these other potential problems through asking the patient for symptoms indicating the problem is present, examining the patient to look for these problems and running further tests to identify these problems. Even if the problems are not present at the initial assessment, they can develop later so armed with this knowledge the doctor can be alert for them developing through history taking, clinical examination and running tests in the future. For example if a patient is seen with a heart attack (myocardial infarction) there are a variety of complications the doctor will be aware of and monitor for such as heart failure or cardiac arrest.
  • What treatment should I offer? The range of possibilities of treatment and the range of responses to treatment – what are the different alternatives of treatment (not just medication)/ help available, how likely the diagnosed condition will respond to treatment, how long this improvement will take, what are the signs of this improvement taking place and what side effects may occur with treatment and how to identify these. If the treatment fails and the diagnosis is correct what are the likely causes for treatment failure (e.g. maybe not taking the medication or not changing lifestyle factors) and how to identify them. Further treatment option knowledge is also triggered at this point. Notice how, as in the above examples, diagnosis links into other types of knowledge, in this case pharmacology and treatment guidelines. The doctor can discuss with the patient these important details and ask them what treatment choices they want to make. The doctor is reducing the information asymmetry deficit. For example if a patient presents with high blood pressure the doctor can discuss what the different options are e.g. lifestyle changes, medication and when to review them to see if succeeding or what changes in treatment are needed.
  • What do I expect to happen in people with this diagnosis? The range of possibilities of outcomes seen with this diagnosis. Most illnesses don’t have a fixed outcome but have a range of probable outcomes. This allows the doctor to discuss these details with the patient. The range of factors that are associated with better and worse outcomes are also linked with the doctor’s knowledge about the diagnosis and allow the doctor to look for the presence of them and modify them if possible. For example, if a case of cancer is seen the doctor will try and identify the size of the tumour, whether it has spread (metastasised) including to local tissues or to lymph nodes or to other areas of the body. He will also look for other factors that may affect outcome such as socioeconomic class, other factors that can be modified e.g. if smoking worsens the outcome of the cancer that can be targeted with smoking cessation. For some tumours genetic testing of the tumour can take place to identify targeted treatments.

It can be seen that diagnosis is provisional and is always open to review as more information comes to light. It is the hub of linked information that the doctor has learned about the illness that guides the doctors management plan: what tests are run, what signs or symptoms are observed for, how to recognize if the diagnosis is wrong, what other illnesses may also be present, what treatment options are discussed and chosen, what to expect in terms of outcomes and what further information is sought to refine the outcome and improve it. Doctors learn about medicine by learning about a diagnosis and the interlinked information as described above. 

Diagnosis can be thought of as a quantum reflexive hyperlinked seed. Quantum reflects the uncertainties as to whether the diagnosis is right, outcome, treatment and so on. Reflexive in that the information associated with the diagnosis includes procedures to monitor whether it is accurate or, like the phoenix, be immolated to be replaced by a new diagnosis. Hyperlinked in that the diagnosis is a hub that links to multiple domains of information as described above. The seed describes the compact nature of a simple term like the diagnosis yet jam-packed with the information and procedures needed to grow a management plan to help the patient with the right environment of a doctor with the ability to respond and act on the information from the patient.

                

Wednesday, 12 November 2014

To boldly go….(where Anglophone psychiatrists rarely have been before)


 
I went to the EASE conference in Copenhagen for 3 days.
(EASE =Evaluation of Anomalous Self-Experience)
It was the best psychiatry conference I’ve ever been to.

The purpose of an EASE interview is to enquire about a whole range of unusual experiences called disorders of the self (or self-disorders) that were described initially in patients with schizophrenia (or dementia praecox) by German psychiatrists nearly 100 years ago that have been largely lost to Anglophone psychiatry .

The EASE was devised by Prof Parnas and collaborators such as Lennart Jansson, Paul Moller,  Peter Handest, Jorgen Thalbitzer, Dan Zahavi.

It’s based from a philosophical and phenomenological viewpoint. It uses terms like ipseity, hyper-reflectivity that I don’t trust myself to explain properly.

I strongly advise going to the website (which is in the process of being refreshed as of 12/11/14) www.easenet.dk with better descriptions and links to reading materials.

So what was so great?
·         Whole new world of patient experiences that were closed to me
·         The tradition of (European)  continental psychiatry
·         The implications of self-disorders clinically

Well it was refreshing and eye-opening to me to discover a whole world of unusual experiences that I was dimly aware of at best and unaware of usually. The correlation is of course that I didn’t ask my patients about these experiences. These experiences include feeling detached from the flow of time, from their own thoughts and bodies, from merging with external objects, from feeling an absence of their core being and more. 

The EASE interview (which usually takes place over several sessions and can be quite lengthy) helps you to ask about these experiences and categorise them. Prof Parnas strongly discourages a structured interview approach (he calls it “an atrocity”). He also cautions that “humility is essential” when categorising these existential experiences and for psychiatrists to avoid becoming “biological idiots”.

Germans wrote the great songs of psychiatry from the late 19th to early-mid 20th century. There are the German Psychiatry “Beatles” of Kraepelin, Kurt Schneider, Jaspers and Bleuler.
To modern Anglophone psychiatry, Bleuler was the Ringo Starr of this quartet.  In US-UK-Down Under eyes Kraepelin split the psychosis based on course, Schneider using First Rank Symptoms (used as the basis of “core schizophrenia”), Jaspers defined psychopathological terms and Bleuler just came up with the name “schizophrenia”. The reason for this is that Bleuler’s concept of schizophrenia (which included a lot of unusual experiences assessed in EASE) was overly expanded in the US to include a lot of cases of depression and personality disorders. This problem was highlighted in the US-UK diagnostic study and explained the very high rates of schizophrenia in the US particularly New York. The yanks then decided to standardise on the British version believing it to represent Schneider’s concept of schizophrenia. The Brits however had made an error of their own, they had too narrow a concept of Schneider. Kurt Schneider himself had described unusual experiences similar to Bleuler on a spectrum with First Rank Symptoms at the extreme end of the spectrum. This error was compounded by DSM treating First Rank Symptoms as delusions (e.g. of thought broadcasting) not as experiences.
Denmark for obvious geographic reasons is still influenced by the original German concepts untainted by Anglophone misconceptions. To me, it was fantastic to hear our Danish hosts switch fluently from perfect English to German and Danish in describing psychopathology.  There is still this strong tradition of Continental psychiatry paying close attention to the source materials.
 Bleuler stated that the delusions and hallucinations were secondary symptoms to the primary disturbances in autism, affect, associations and ambivalence. A lot of these disturbances are measured in the EASE scale which leads me into the third point, the clinical implications.
My viewpoint on the classification of psychosis has changed with experience and research. Initially I viewed schizophrenia and bipolar disorder as very separate illnesses. Over the past 10 years I’ve changed my conception of psychosis to a spectrum (like a rainbow) with schizophrenia and bipolar disorder as different colours on this spectrum at nearly opposite ends (like violet and red on a rainbow) – see my first blogpost “Utility without Validity”.
I may be at a tipping point of a change back to viewing them as more separate than before. This is because disorders of self are far commoner in schizophrenia than in bipolar disorder (see the papers on the EASE website, one paper said disorders of self were 9 times commoner in schizophrenia compared to bipolar disorder). There are similar amounts of disorders of self in schizophrenia and schizotypal disorder. This indicates that schizotypal disorder and schizophrenia lie on a spectrum.
A gradient of severity of disorders in self seems to exist
1.       Schizophrenia and schizotypal disorder
2.       Bipolar disorder/ other psychosis
3.       Other mental disorders
4.       No mental disorder
This would seem useful in identifying and separating schizophrenia from other mental disorders, the differentiation from schizotypal disorder being one of degree of positive and negative symptoms present. There was no relationship between self-disorder scale scores and borderline personality disorder symptom scores.
There were other clinical implications. One of them was that in a sample of patients thought to be at high risk of developing psychosis, it was the presence of disorders of self that predicted transition to psychosis best. The transition rates to psychosis in this at risk group is dropping to perhaps 20—25% in 2 years. If this finding is replicated this improves our ability to predict transition and avoid unnecessary treatment.

Disorders of self are not merely straight forward neuropsychological impairments by another name and didn’t correlate with neuropsychology scores.
For me the biggest implication is that if these disorders of self are the fundamental disorder of schizophrenia, the soil from which the other symptoms grow out of?
If so, what effect do antipsychotics have on this? I suspect they may dampen but not remove them. EASE assessments are done when the patients aren’t floridly psychotic yet they still seem to describe these problems as active. So current antipsychotics may do a good job on delusions and hallucinations (a far better job than e.g. CBT for psychosis or CBTp) but not on these disorders of self.
Further research would also be needed on how disorders of self effect prognosis and risk. In the meantime I am going to be using EASE interviews on a range of patients, some with schizophrenia, some with psychosis but unlikely to be schizophrenia and other patients without a psychosis.
There no CBT models of these type of problems and no apparent CBT interventions for them (indeed in the COMPARE CBTp trial high scores on the “disorganisation” item are an exclusion criteria from the trial and many disorders of the self do seem linked to hebephrenic type pictures and hence high scores on the “disorganisation” item).  
You could argue an existential problem like disorders of the self should respond to psychodynamic therapy but early experience of this in schizophrenia was discouraging. It has been modified recently to reduce paranoia induced by the therapy and perhaps this might be an avenue of approach. My hunch is these experiences are so dislocating that it might be a bit too hard for “the couch”.
So disorders of self could revolutionise how we conceive of schizophrenia but could also pose a massive challenge in how to address and help them.

May we live in interesting times…

Saturday, 13 September 2014

Classification in Psychiatry presentation


Classification in Psychiatry - Presentation

Classification In Psychiatry
Categorisation 

http://www.youtube.com/watch?v=O8oAU3QGy2c 

Categorisation II
Describe what you have just seen
Probably used words like “goal” “football”   maybe even “Scotland”  or for the more advanced “good triumphing over evil”
We experience raw streams of data that our brain subdivides into categories and concepts to help us make sense of this 
We think abstractly using the same method of concepts/ categories
This happens at basic animal levels of consciousness – “do we mate with it/ eat it/avoid or go round it/run away from it”?

Categorisation III
Doctors often see patients in time critical situations e.g. brief appointments
Other stressors could be e.g. seeing patient at 3am, being aware of multiple patients to see after this one, caseloads of 100s
Often have to make decisions about patient such as admit/not admit, what treatment to start or change etc
Need a robust system to help them make good decisions under alll kinds of pressure

A,B, C, D Model of Patient attributes
A - What patient shares with all other patients
B - What patient shares with some other patients
C – What is unique to this patient
{D- What patient shares with everybody else}
If concentrate therapeutic efforts solely on A, offer same treatment to everyone
If concentrate therapeutic efforts solely on C, can’t extrapolate from this patient how to treat other patients
If concentrate purely on B lose sight of the person
Must make therapeutic efforts on A,B,C and D


Why Do We Need Classification?
Allows communication between professionals
Allows groups to be defined for research to gain information on
Range of likely outcomes (prognosis)
Response to treatment
Important correlates such as bio psycho social features
Causes of the classified disorder (and explanation)
Statistics for administration, management and budgeting
Eligibility for care both from services but also family/society
Facilitate appropriate payments for care
Reduces potential for abuse e.g. of psychiatric diagnosis

The Status of a Diagnosis
Diagnosis is an abstract concept used to summarise complex information about a patient’s health state
It doesn’t exist as a “thing”
It is ALWAYS provisional
People may be given a diagnosis but they are NOT the diagnosis
It can have powerful effects on people’s lives. Not all intentional or harmless


Essentialism & Carving Turkeys
“Essentialism” suggests that for example illnesses can be separated into “natural kinds”
These separate entities are distinguished by points of rarity and the categories have validity
(Pneumonia is different from myocardial infarction, and can be further subdivided into a variety of aetiological causes)
So diagnosis is supposed “to carve nature at the joints”
BUT nature is not a giant multi-limbed turkey
Mental disorder particularly hard to separate from each other

Promiscuous Reality and Elephants
http://www.youtube.com/watch?v=-Pknme2ahwA

What is Promiscuous Reality?

Multiple viewpoints can describe a “piece” of the whole truth
Putting all these viewpoints together can increase your knowledge of the whole though maybe not even the totality of whole truth
Different viewpoints can have different purposes
Multiple “models” of mental of disorder – biological, social, cognitive, psychodynamic and so forth
These can all be useful in understanding and guiding help for patients
They do not necessarily exclude each other
Pragmatic realists recognise different classifications can be used depending on their Utility (usefulnesss)

Hepatic Lobule: multiple views
Can look at anatomical view : hexagonal structure
Can look at biliary flow point of view : centred on bile duct drainage area

All views valid and can choose which view suits your purpose.


What is Validity? I
Construct validity. Construct validity refers to the extent to which a particular measure relates to other measures consistent with theoretically derived hypotheses
Content validity refers to the extent to which a measure represents all facets of a given social construct (non-statistical expert opinion)
Convergent validity refers to the degree to which a measure is correlated with other measures that it is theoretically predicted to correlate with e.g. intelligence test correlate with e.g. exam results

What is Validity? II
Discriminant validity tests whether concepts or measurements that are supposed to be unrelated are, in fact, unrelated i.e. separates “natural kinds”
Predictive validity measures how well the construct can predict future events ie. Prognosis  as well as treatment response
Criterion validity. Criterion validity is measuring something that is external to the measuring instrument itself, called the criterion, that is representative of the construct. In medicine we often use biomarkers  e.g. BP, blood tests, X –rays etc

What is Validity? III
Concurrent validity refers to the degree to which the construct description/ measures correlates with other measures of the same construct that are measured at the same time
Face validity is a non-statistical  estimate of whether a test appears to measure a certain criterion; it does not guarantee that the test actually measures phenomena in that domain.
Procedural validity. Procedural validity refers to the adequacy of a new diagnostic procedure in replacing or simulating some existing procedure e.g. use of standardised interviews to detect mental disorder over non-standardised. Not validity of construct itself.
Validity of Psychiatric Disorders (Robbins & Guze 1970)
1) Clinical Description (including symptom profiles, demographic characteristics, and typical precipitants),
2) Laboratory studies (including psychological tests, radiology and post mortem findings) extended to other external validators e.g. molecular biology, cognitive neuroscience
3) Delimitation from other disorders (by means of exclusion criteria)
4) Follow-up studies (including evidence of diagnostic stability), 
5) Family studies showing familial aggregation, specificity for same or related disorders


Validity of Psychiatric Disorders (Kendler 1980)
Antecedent validators 
familial aggregation
premorbid personality
precipitating factors 
Concurrent validators 
psychological tests (?external criterion?)
 Predictive validators 
diagnostic consistency over time
rates of relapse and recovery
response to treatment


Lumpers v Splitters
Lumpers emphasise lack of distinction between separate categories and high degree of comorbidity
Splitters emphasise differences between members of bigger classes because of differences in treatment response / prognosis

Problems of classifying Mental Disorders
Brain is most complex organ in body by far
Functioning of brain poorly understood : what we do know is still difficult to understand how it translates into “outputs” such as thoughts, feelings, memories 
(Physiology and pathophysiology poorly understood)
“Outputs” of brain extraordinarily complex and affected by external factors such as culture and very hard to objectively measure
Given complexity of outputs, the role of external factors such as culture, lack of knowledge of functioning of brain, difficulty objectively measuring outputs an aetiological classification is very difficult 

Reliability
“Without Reliability there can be NO Validity (OR UTILITY)”
If a diagnosis can’t be reliably agreed upon it has low utility
Inter-Rater Reliability in terms of diagnosis can be defined as the degree to which different observers can agree on the presence of a diagnosis in the same patient
Often measured using the Cohen’s kappa concordance statistic : the degree of agreement between 2 raters, greater than chance
Also can be “weighted” for multiple categories, taking into account how close categories are together for agreement (e.g. yellow/orange more disagreement than red/violet)

Measuring Reliability
Kappa Agreement
< 0 Less than chance agreement
0.01–0.20 Slight agreement
0.21– 0.40 Fair agreement
0.41–0.60 Moderate agreement
0.61–0.80 Substantial agreement
0.81–0.99 Almost perfect agreement
(DSM 5 used much lower thresholds to justify diagnostic categories as having good reliability)

Inter-Rater reliability of ICD10 Diagnosis
For schizophrenia is substantial 0.79 – 81 but less so for subtypes 0.40- 0.74
For Personality disorder subtypes only slight to fair 0.07-0.43

Improving Inter-Rater Reliability of Diagnostic Agreement
Standardising how and where patients are assessed
Standardising what questions are asked
Standardising training of raters
Standardising how answers and observations are interpreted e.g. definitions of symptoms
Standardising diagnostic definitions
Standardising the rules how diagnosis are made e.g. in terms of co-morbid symptoms, co-morbid diagnosis, co-morbid aetiological factors e.g. substances
NB Test-retest reliability 

Spectrum 
Many medical disorders exist on a spectrum which includes normality, the extremes of which clearly represent illness but with a "contentious" zone at more central values. An "expert committee" is usually formed which decides the best compromise for deciding a threshold. This threshold is often decided on the basis of associated poor outcomes such as death and other disease events.  Sometimes there is a threshold at only one end of the spectrum but often at both ends of a spectrum too

Examples include blood pressure, blood glucose, bronchial reactivity, depression/anxiety symptoms 

Within medical disorders often there can be mixed spectrum of clinical features and people can be put into separate diagnostic categories depending on which clinical features predominate . (Examples include mixes of bronchitis and emphysema, or psychosis and mania).

Utility of Colours
Number of colours varies with culture e.g. Newton said 6, some cultures recognise only 2, others up to 7.
Colours are cultural constructs separating spectrum into categories
However people from all cultures are equally able to recognise difference in hues/shades 
Recognising differences in colours has usefulness : in natural and artificial world. 
PANTONE is a system of allocating codes to different shades so that manufacturers, printers, artists etc can communicate with each other and be consistent when using colours

Utility without Validity : SCZ and Mania

Can reliably separate: ICD 10 kappa for schizophrenia 0.79-0.81 and for bipolar, manic disorders to be 0.69-0.77
Has predictive value for outcome: AESOP study if presented with Mania had 3-4 times better chance of symptom & functional recovery at 3 and 10 years than presenting with Schizophrenia
Has predictive value for treatment: Lithium effective in bipolar mania (and bipolar, depression) but not schizophrenia. Antipsychotics can be effective for  both bipolar mania and schizophrenia but not bipolar, depression (quetiapine low dose may be effective for bipolar dep)
Bipolar on average less cognitive impairment than SCZ
More likely to have same type of disorder inherited (not purely tho)

Diagnosis 0.0
These are problems that may be the focus of clinical attention or may be referred to clinicians for help
Not usually “illnesses” per se with a “disease” cause but often mixed groups and very culturally based
Often need a diagnostic “code” to enable someone to access help and for the clinician to be remunerated (or allowed to help)
Maybe contentious as some do not feel should be “medical”
Examples include relationship problems, Oppositional Defiance Disorder,  anger management issues, ?paraphillias, some plastic surgery problems

Diagnosis 1.0
Descriptions of clinical states that are problematic and widely thought to need medical attention
Often describe  syndromes i.e. collections of clinical features occur together , often little validity to the distinctions
Not aetiological i.e. not based on cause of the disorder so members of this group often have different causes (known or unknown)
As not aetiological not able to “explain” and treatment responses /outcomes highly variable, lack of lab tests; cultural limitations
Many psychiatric disorders e.g. depression, schizophrenia, ADHD, also “functional” medical disorders and e.g. “fever”

Diagnosis 2.0
Fully aetiological basis known and external validating criteria such as lab tests to confirm diagnosis and monitor progress
More able to sort in to truly valid categories
As aetiological basis known, better able to predict outcomes and treatment responses, develop new treatments
Explanation of disorder known : greater patient information and public health interventions possible
Many medical conditions but also e.g. alzheimer’s disease, wernicke-korsakoff, steroid induced depression

Stigma and other drawbacks 
By concentrating on the diagnosis can lose whole picture especially if “overforce” into ill matching category
Stigma: people often get associated with their diagnosis e.g. epileptic, diabetic
This can lead to self-stigma, stigma from other people, and from healthcare professionals based on stereotypes of that illness
This stigma can be even more distressing than the disorder itself
Reification “over estimate” the degree of “predictive knowledge” and “validity” of the diagnostic construct e.g. SCZ is an illness not a disease (as pathology unknown in most cases)

Comparison with General Medical Diagnosis  Szasz fallacy
Disease can only mean something people "have," while behavior is what people "do". Diseases are "malfunctions of the human body, of the heart, the liver, the kidney, the brain" while "no behavior or misbehavior is a disease or can be a disease. That's not what diseases are.”
Says mental illnesses are metaphors
Ignores the conceptual basis of general medicine
Assumes all general medical problems have identified pathology
Ignores value judgements made even in “objective” lab tests
Assumes perfect knowledge of pathology and physiology

Diagnosis in Medicine – Problems
60% of MDDUS negligence claims v GPs  are due to failure to diagnose
Diagnostic errors are the most common source of the medical malpractice payments, the most costly and the most dangerous when it came to patients’ health
A systematic review of studies of the autopsy calculated that in about 25% of autopsies a major diagnostic error will be revealed. 
This rate has decreased over time and the study projects that in a contemporary US institution, 8.4% to 24.4% of autopsies will detect major diagnostic errors.

Causes of Diagnostic Errors 1
Anchoring bias (COMMONEST) – locking on to a diagnosis too soon and failing to adjust to new information.
Availability bias – thinking that a similar recent presentation you have encountered is also happening in the present situation.
Confirmation bias – looking for evidence to support a pre-conceived opinion or notion, rather than looking for information to prove oneself wrong.
Diagnosis momentum – accepting a previous diagnosis without applying sufficient scepticism.

Causes of Diagnostic Errors 2
Overconfidence bias – Over-reliance on one’s own ability, intuition and judgement.
Premature closure – similar to confirmation bias, but more like jumping to a conclusion.
Search-satisfying bias – A “eureka” moment that stops all further thought on the matter
I would also add 
treating the test result not the patient
“over-forcing” patient into a diagnostic category they don’t fit well into

Comparison with Medical Diagnosis Reliability
“…most indexes of agreement between pathologists ranged from poor (needle biopsy 0.21) to moderate (necropsy/surgery 0.57).” 
160 cases reviewed  3 pairs of neurologists “with a special interest in stroke.”8 The kappa was only “fair to good” in most categories of ischemic stroke, with a high of 0.70 for oral contraceptive-related stroke and a low of 0.28 for lacunar infarcts; the average kappa for all categories was 0.53 
Knee osteoarthritis kappa = 0.1 renal artery stenosis kappa =0.43
that interrater reliability is no higher in many nonpsychiatric medical specialties than in psychiatry 

Comparison with Medical Diagnosis Validity
Many medical problems have unknown pathology and would fail to meet “validity” tests
Headaches, migraines, CFS/ME, Fibromyalgia Irritable Bowel Syndrome
Up to 40% of referrals to different medical OPs have these “functional disorders”
May medical problems have “cultural” overlays in presentation e.g. myocardial infarction

  • Even when pathology known and "validity gap", often general medical treatments have similar effectiveness to psychiatric treatments

Comparison with Medical Diagnosis  Spectrum
Many accepted medical disorders lie on a spectrum with “normality”
Examples include hypertension, non insulin dependent diabetes, asthma
Many medical disorders don’t have clear cut boundaries with similar disorders
Example: bronchitis/emphysema, unstable angina/myocardial infarction

History of Classification – Early Days
Initially mental disorders thought to be somatic in origin
Gradually introduction of ideas of “mental” disorders with varying degree of somatic input 
Every country, every hospital sometimes even every psychiatrist had a separate diagnostic system
Research papers often had to include lengthy descriptions of each patient so that readers could compare to own patients e.g. Aubrey Lewis paper on depression 40-50 pages had 20 pages on describing each patient
Psychodynamic classifications important in US from early-mid 20th C

US/UK Diagnostic Project
Noted high rates of schizophrenia in US especially New York compared to UK
Group of London psychiatrists visited NY in late 65-70 and using standardised psychiatric interviews and a standardised way of making psychiatric diagnosis
Found high rates of schizophrenia in New York due to their use of a “psychodynamic” diagnostic criteria, many of these cases would be diagnosed with mood disorders or personality disorders in the UK
Highlighted the variability of diagnostic practices reduced its’ usefulness for research or communication or statistics or clinical practice

Nomenclature & Classification
Nomenclature refers to the naming of objects in  a classification
These objects are given a description , often with a definition of what is unique to that object
The combination of nomenclature of objects with their descriptions is called a glossary 
The classification ideally should be mutually exclusive and jointly exhaustive : every example (e.g. of clinical cases) described and examples can only be put in 1 place
A Taxon is a group of objects with obvious and important similarities 
Taxonomic hierarchy often used e.g. classification of animals

ISPS (1967) and DOSMED (1992)
Multiple international centres of research in broad spread of developed and developing countries
Used standardised semi-structured interviews and diagnostic procedures
“Broad” definition of psychosis  incidence varied widely by country 
“Narrow” definition of psychosis roughly similar incidence across globe- adding to cross-cultural validity of concept of “Schneiderian” SCZ
Outcomes generally better in developed countries ?less EE ?different aetiology?

Diagnostic Hierarchy
Choose diagnosis that is highest in hierarchy that can explain all symptoms 
  1. Organic disorders
  2. Mood Psychosis
  3. Schizophrenia
  4. Depression
  5. Anxiety Disorders
  6. Personality issues
Prototypic Matching/ Narrative v Operational Criteria

Prototypic matching/  narrative classifications describe “typical cases” (cf blue bloaters/pink puffers). Professionals match patient in front of them to closest description in classification 
Clinicians prefer this type as quick and convenient

Operational criteria list a set of rules to make a diagnosis in a particular patient (cf making a diagnosis of myocardial infarction) such as mandatory features, exclusion criteria etc. 
Researchers prefer this as more get more standardised homogenous groups

Multi-axial Classification
With most diagnosis often non-aetiological, often ignoring social circumstances, high rates of comorbidity
Can list important factors in different “axes”
Eg. DSM III & IV had
  1. Clinical syndromes/disorders
  2. Personality disorders, mental retardation
  3. Medical conditions
  4. Psychosocial and Environmental Stressors
  5. Global Assessment of Functioning

The International Classification of Diseases
The standard diagnostic tool for epidemiology, health management and clinical purposes.
Every country has to send health statistics using ICD codes to UN
In its 10th edition, with 11th coming out soon
6th edition started providing psychiatric codes but with no description (similar to other health problems) 
From 8th edition onwards a “glossary” produced with descriptions of each psychiatric code to improve standardisation of practice
10th has a main version of a  glossary with prototypic descriptions, a DCR with operational criteria and a simplified primary care version

Diagnostic Statistical Manual
Introduced to produce codes for variety of admin uses and descriptions of these codes for US 
Gives ICD codes for disorders and increasing similarity to ICD
DSM editions I,II used psychodynamic concepts and aetiology
DSM III revolutionary in 1980 : operational criteria, multi-axial classification, dropped Freudian aetiology, aimed for reliability
Latest edition DSM V controversial: felt to be too low thresholds to include too many “contentious” cases (Yanks worry though that too restrictive would deny people access to help)
Most commonly used system in research

Alternative Diagnostic Systems
France uses a psychodynamic influenced classification for child psychiatry
ICD as has to be used internationally incorporates many of different traditions of psychiatric diagnostic practices in their classification

Diagnosis as part of Formulation
Formulation is summary of all relevant clinical information including diagnosis
Should guide treatment and management of patient
Should tell you “why does this patient present with this type of problem at this particular time (and still does)?”
Can be divided into predisposing, precipitating and maintaining factors
The types of factors can be divided into biological, psychological and social
BIOPSYCHOSOCIAL formulation

Alternatives to Diagnosis: Why?
Lack of validity
High rates of comorbidity
High levels of assumptions contained within diagnosis
Dislike of “medical” emphasis/language/system and perceived “biological orientation” “Disease based model”
Diagnostic system may not suit their practice: 
e.g. primary care where the cause of the stress (usually psychosocial) & most often mixed anxiety and depressive symptoms
Psychotherapists and psychologists with “office based practice”
Ignores social context & locates pathology in individual

Alternatives to Diagnosis : Symptoms
Can just use symptoms : no assumptions about relationships or associations so no concerns re : validity
Individual symptoms can have some predictive validity
“most scientific” as just concentrate on what is present and can measure these
Some treatments such as eg CBT focus on individual symptoms
Very time and cognitive resource intensive
Often “diagnosis by proxy” as have to take into account aetiology eg substance-related anxiety treated differently than free floating
Often medical treatments effect multiple symptoms at same time

Alternatives to Diagnosis : Dimensions
Dimensions are  Groups symptoms/clinical features  into categories of related symptoms 
Often describes patients better than simple diagnosis (1 bit v multiple bits) in terms of clinical picture, prognosis and treatment responses
Also requires additional aetiological information 
Often prone to diagnosis e.g. describing patients with high levels of hallucinations/delusions as “paranoid schizophrenia” in head
Complexity can be hard to hold and manipulate in head whilst making decisions as well as collecting statistics, research (due to large no. of groups so often use correlation)
Multiple dimensions become like diagnostic comorbidity 

Alternatives to Diagnosis : Purely Psychosocial formulations
DCP trying to develop “paradigm shift” 
Intent is to provide a narrative formulation with less emphasis on biological factors
Trying to identify psychological processes as basis of classification
More useful therefore for psychotherapy and “office based practice”
Unknown reliability and validity
Unlikely to be useful to “medical psychiatry”
Issues of communication errors if used exclusively by psychologists when talking to psychiatrists

Further Reading
ICD 10 (mandatory until ICD 11 comes out)
DSM V (know about)
“A Companion to the Classification of Mental Disorders” Cooper and Sartorius
Read chapter on Classification in your main textbook e.g. Shorter Oxford Textbook on Psychiatry 
“Distinguishing between the validity and utility of psychiatric diagnoses” Kendell, Robert;Jablensky, Assen The American Journal of Psychiatry; Jan 2003; 160, 1
“Models for Mental Disorder”  Tyrer and Steinberg

  • Philosophical Issues in Psychiatry Volume 2: Nosology

Friday, 1 August 2014

First game of Call of Cthulhu



Call of Cthulhu is a roleplaying game (for more info see http://en.wikipedia.org/wiki/Call_of_Cthulhu_(role-playing_game)

It is based on the works of HP Lovecraft http://en.wikipedia.org/wiki/H._P._Lovecraft
It is set in a universe where vastly powerful dangerous beings care naught for humans and often have various plans which incidentally lead to the destruction of humanity. A band of intrepid investigators try and thwart their plans at great risk to their bodies and minds.

The most famous of these powerful near-gods is the titular Cthulhu or "squid-head" as I affectionately call him.

This is a classic game, in its' 6th edition with a 7th edition coming out. I've wanted to play it since the 80s and tonight our little band (me as Games Master but also controlling two characters and Jake and Chris) played our first game. It can be set in any time period but our game was set in the 1920s - the classic time period for the game.

In the game, the more the horrific truth dawns on the investigators and the more the horrific trauma they experience they lose Sanity. They can go temporarily or indefinitely insane. (Interestingly the types of insanity are often various phobias but with many types based on DSM - a sign of the cultural penetration of that classification system).

Sanity is the most crucial statistic in the game. Investigators can come from many backgrounds and that includes psychiatrists (often called alienists in this era). Psychiatrists are quite useful in the game as they can use psychoanalysis to help investigators with their Sanity losses (though often takes a while). There aren't many effective psychiatric drugs in this period.

I've bought several campaigns but we'll start off with some stand alone adventures before embarking on the various complex world-destroying plots.

Our happy band includes Jake's gumshoe, Chris' Russian ex White Guards officer refugee (who despite being the fighter of the group ended up being knocked out by a hobo with a table leg, the wimp). I run 2 characters, a top notch psychiatrist (of course) based on Rivers of WW1 "Regeneration" trilogy fame but who also happens to be black (leading to problems in the racist US of the 1920s) and a rich female dilettante with a Cadillac and a shotgun.

We've just finished a Middle Earth Roleplaying Game campaing traipsing all over Endor from the frozen North to burning South via Mirkwood. This was a good humoured game, so I'm hoping I can deliver a horrifying, creepy tone appropriate to this new game

Tuesday, 29 July 2014

Trees or the Wood: Symptom based or diagnosis based approaches in Mental Health


The Trees or the Wood: Is a symptoms based approach better than a diagnosis based approach in Mental Health?

Thanks to Dr Ivani Fulli who requested this blog.
The short answer is:  it depends. People who confidently assert that a symptoms based approach or diagnostic based approach is better are omitting to say “for the type of work/ research that I do”. The different approaches have different strengths and weaknesses, of which I will outline some below.

What are the differences?

Symptoms can be thought of as individual complaints or deviations from normal in individual fields. (I’m not going to spend ages with exact definitions as it will suck my enthusiasm).  Doctors sometimes focus on individual symptoms as an important clinical concern and focus of treatment e.g. pain. Sometimes individual symptoms are regarded as particularly important even when using a diagnostic-based approach, often because they are associated with risk or a particularly significant clinical outcome (examples include suicidal/homicidal thoughts).
Now a patient or client (I will stick to patient rather than use both terms) will have their own symptoms.
A diagnosis is based on “archetypes” and in mental health with little validating lab tests etc  based on “vignettes” or “clinical pictures” of what a typical patient will appear to the treating professional. These archetypes are often described with typical symptoms and other typical features and also what features would disqualify them from being given that diagnosis. DSM3 and onwards used specific lists of symptoms and other features which patients had to have before being given this diagnosis.
The diagnostic criteria in psychiatry are called polythetic which in practice means two different patients with the same diagnosis can have different symptoms (and even with the same type of symptom can vary a lot e.g. people with persecutory delusions often have different content e.g. one may be being pursued by the IRA and another may be being attacked by the illuminati).
So a worry people have is that if people have different symptoms this creates uncertainty as to how similar they really are and if you can translate research from this into the patient they see in front of them. It depends on course how good the individual diagnosis is at bringing together people with problems into a category that will predict treatment responses and clinical outcomes.
A good example is depression where people don’t even have to have depression (so long as they anhedonia for DSM or anhedonia and fatigue for ICD10) or panic attacks which can take many forms (but few psychologists object to the use of panic attack as a concept). However polythetic criteria exist in general medicine too such as heart attacks where people don’t have to present with typical crushing chest pain so long as they have enzyme and ECG changes. There also polythetic criteria for conditions in medicine with no objective lab tests to confirm e.g. migraine, chronic fatigue syndrome/ME, polymyalgic rheumatica.
Nevertheless, some people want to stick to symptom only approaches as they feel it’s more rigorous than a diagnostic approach as it’s based on what’s there not what is assumed to be a common condition as assumed by diagnosis.
However it’s rarely a pure symptom based approach. Often it’s symptom in context as management varies. How you treat anxiety brought on only by alcohol withdrawal is different from anxiety in the context of going to the supermarket only. Hallucinations in the context of LSD intoxication are treated differently from hallucinations with no clear cause in clear consciousness. By using these contexts and rules you are effectively making a “diagnosis by proxy” : the same symptom with different causes/ contexts is treated differently and has different prognosis . You aren’t just looking at symptoms but placing them in a context with other data. Sometimes they are also organised into groups of symptoms such as “depressive symptoms” or “panic attacks”.  Some people will organise into “dimensions” but that is a separate topic.
Think of trees and wood, the wood (diagnosis) is comprised of trees (symptoms and other clinical factors such as symptoms only caused by intoxication or withdrawal).  How you conceptualise the problem in terms of research and management depends on whether you target the trees or the wood. Now the trees are there and have an existence outside of the human mind. The wood is an abstract conceptualisation of this group of trees and exists in human minds. In fact for all illnesses  in medicine this applies. The pathology, the symptoms, the disability are all real but how we conceptualise them are abstract concepts.
Now as noted above symptoms based approaches often involve some context and grouping of figures, perhaps a copse rather than a wood.

Research Differences

Apart from the problem of people with the same diagnosis having different symptoms, for some research it may be more fruitful to examine things at the symptom level. It may be easier to track the fluctuations of individual symptoms. It may be more scientifically rigorous just to measure individual symptoms rather than set semi-arbitrary cut off points for wellness or relapse or recovery (e.g. 50% reduction in symptoms, why not 49% or 51%?).
This can give you a nice, scientific set of numbers. However it can be a bit overwhelming as most patients I see have many symptoms. So people often group them together ; “diagnosis by proxy”. And for many treatments you want to know how similar the patients in research trials are to your own patients. This often means setting  various rules e.g. psychotic symptoms when not intoxicated with substances and again getting close to diagnosis if not using diagnosis outright.
Diagnosis based research often also uses measures of symptoms as well such as HAMD for depression or BPRS or PANSS for psychosis symptoms. So this incorporates the best of both worlds.
Of course for certain types of interventions that target specific symptoms then you need research to evaluate this. This can include painkillers for pain, hypnotic drugs for insomnia or behavioural experiments for symptoms in CBT. However these still need context e.g. if behavioural experiment for insomnia then it may differ if alcohol is the cause.
In summary, symptom based research can be regarded as more scientifically rigourous but still needs to be organised at a higher level often for it to be useful clinically. Useful research for interventions can be done if targeted only at symptoms but diagnosis based research often also incorporates symptoms data.

Communication

In health you often work with other people such as GPs, CPNS, social workers etc. People don’t like the comorbidity in mental health, people often have multiple diagnoses. However imagine the length of letters and other communications if you just listed all symptoms the patient had and how they had changed. It is simpler to refer to diagnosis and any important changes or symptoms (such as suicidality). Of course you could group the symptoms but you are using diagnosis by proxy in this case.
With patients sometimes it is easier to talk about diagnosis but depends on how good the diagnosis is (reliable, how predictive of treatment and prognosis, level of validity) rather than individual symptoms. On the other hand, patients are often interested in WHY they have problems and in may find it easier to link individual symptoms to past experience.

Treatment Differences

Differences in symptom or diagnosis based approaches can be seen in their management and treatment. Doctors may use medications to treat specific symptoms (painkillers, hypnotics for insomnia) but they often use medications to treat groups of symptoms simultaneously. So  if someone had a diagnosis of depression then treating with antidepressants or schizophrenia with antipsychotics or mania with lithium (or antipsychotics).
Now these drugs often target certain symptoms within that diagnosis better than others e.g. antipsychotics are better at treating hallucinations or delusions than they are treating primary negative symptoms (not caused by e.g. mood or hallucinations/delusions) of schizophrenia.  As a rule however, often drugs treat multiple symptoms at a time (sometimes with different levels of success and at different rates of time).  You still measure or enquire about the symptoms because this is how you can tell if the treatment is working (even in general medicine with its’ lab tests you still have to ask about the patient’s symptoms as you treat the patient, not the lab test as no test is 100% accurate).
In some types of psychotherapy e.g. CBT the focus is more on symptoms. The formulation of the patient will identify what are the more core problems driving the rest. The therapist and patient will decide together what symptom to work on first. There will be a mixture of cognitive and behavioural techniques applied to the first symptom. Once this has been tackled, the therapist and patient will move onto the next symptom/problem and hopefully the patient will have learned transferable skills to make tackling the next symptoms easier/quicker. (“I’ve taught you how to use the saw on the first tree, now saw the next tree down”). These steps are repeated until hopefully the symptoms are reduced (or easier to cope with) and/or the patient can on their own tackle the remaining symptoms or problems.
It’s a bit more complicated than that and there are obviously strong effects from the therapist-patient relationship that is having positive effects on the symptoms but that is a crude summary of how someone might use a symptoms based approach to treat someone.
So depending on the type of intervention you offer, either a diagnosis based approach or a symptom based approach will be more fruitful.   A symptom based approach requires more intensive time input than a diagnostic based approach.

Summary

Symptom based approaches are rarely purely symptom based as they have to incorporate contextual data (e.g. in context only of substance intoxication or not) and are often grouped together with other symptoms in a diagnosis by proxy approach. Diagnosis based approaches involve making assumptions.
Symptoms may be more scientifically rigorous when measuring than purely diagnosis based approaches but often need to have context and grouping applied similar to diagnosis. Diagnosis based research often also measure symptoms anyway.
In communicating with fellow healthcare workers, diagnosis plus other important info is quicker than laboriously listing all the symptoms. Some patients may find it easier to link specific symptoms to past events.
Some treatment approaches treat several symptoms simultaneously so a diagnosis based approach is helpful here. A symptom based approach may be more helpful where interventions such as CBT often target a single symptom at a time.
Both diagnosis and symptom based approaches can be used and have different usefulness depending often on how the professional helps people with mental health problems.  Symptom based approaches as noted above are rarely purely symptom based but often involve contextual factors and grouping of symptoms.


Friday, 25 July 2014


 
Utility without validity

Utility and validity

A frequent concern is, if psychiatric disorders don’t actually describe “natural kinds” i.e. clearly separate illnesses such as differentiating pneumonia from a heart attack then this lack of validity means they have no usefulness in treatment or prognosis (utility).

Think of colours

Western and Japanese culture recognises 7 main colours (excluding black and white) other cultures recognise smaller number e.g.  some in Africa recognise 2 main colours. When tested all people from all cultures can recognise differences in tone/ colour when tested. (So clearly separate different colours can be reliably recognised).

Differences between colours are not absolute e.g. orange eventually becomes yellow but the borderline is indistinct. Differences between neighbour colours is more difficult e.g. orange/yellow or indigo/ violet than differences between clearly separate colours e.g. orange/violet.

So this is a spectrum phenomenon (but with an external validated criterion of light frequency/wavelength) that we categorise into separate colours, not by the external criterion but how it appears to us (so the wavelength is assigned to a subjectively decided colour). The number of categories is culturally determined and we can reliably differentiate between colours/ tones if on clearly different points of spectrum but not if close together on spectrum.

We categorise colours despite it actually being a spectrum because we find it useful for purposes of description. We categorise based on archetypes e.g. of orange, of yellow, not clearly separated. The archetype is of the greenest green or the bluest blue etc Note there is no assumption of “clustering” i.e. that in nature, light frequencies/wavelengths encountered will be more common either each named archetype/ category or that the prevalence of light frequency/wavelengths will be commoner in the centre of the archetype/categories light frequency/ wavelength optimum value.

Note Pantone system of allocating number and name codes to varying shades of colour is a form of categorisation using archetypes.

Application to mental disorders

If you assume that mental activities/ behaviours/ symptoms exist on a spectrum (multi-dimensional rather than single dimensional) and are not separated dichotomously from each other or from “normal” range (i.e. are not separate “natural kinds” and not valid separate categories)

You can still apply categories to these dimensions in a similar way to colours above.

These categories form “archetypes” which to be useful need to be
  • Reliably distinguished (neighbour categories harder to distinguish than distant categories)
  • Provide useful information in terms of other associated features, prognostic frequencies (not absolute but increased and decreased rates), guide to treatment based on research, use for stats etc
  • We can expect that differences between “neighbouring” archetypes may be less than those with “distant” archetypes
  • That marginal cases may exist that don’t fit closely into these archetypes (c.f. index levels of caseness in S.C.A.N. interview schedule) but that the optimum number of categories is not necessarily fixed but depends on other factors (c.f. different no. of colours in different cultures) see debates between lumpers and splitters

Now how might this work in practise?


Looking at 2 dimensions: psychotic symptoms and presence/absence of mania. Now some cases of psychosis may have mild manic type symptoms intermittently but overall are closer to the psychosis, no mania archetype. Let’s place them at different part of the spectrum (equivalent to red and violet in he rainbow). Let’s look at one aspect: the effectiveness of Lithium and antipsychotics in treating the presenting picture. We can get the following picture (derived from Cochrane Reviews and clinical practise).

Category
Antipsychotic effective?
Lithium Effective?
Mania, no psychosis
Yes
Yes
Mania with psychosis
Yes
Yes
Psychosis, no/little mania
Yes
No
Normal
No
No

I’ve not described some of the other differences e.g. tendency to different ages of onset, different social class prevalence, different levels of and type of cognitive impairment etc.

We can see from the point of view of a prescriber it is important to distinguish presence of mania and psychosis and to allocate to appropriate category (one can argue the important question is manic yes/no? if no, psychotic yes/ no, give appropriate treatment. Note for a prescriber the individual symptom in this case is unimportant, e.g. auditory hallucination, persecutory delusion, insomnia, what is more important is to which class the symptom in context with other symptoms places the patient into. 

Another important distinguishing feature could be outcome/prognosis. Very few general medical illnesses give an absolute prognosis e.g. 100% guaranteed to recur in a specific time frame. They often give a range of probabilities of outcome.

The AESOP study in the UK looked at people with a First Episode psychosis. They found that people who presented with Mania had 3-4 times better chance of symptom and functional recovery at 3 and 10 years than people presenting with Schizophrenia/ Schizoaffective disorder (a mixture of both psychosis and mood disorder). (From a lecture given at the General Adult Psychiatry Conference in Manchester in 2013).

So can you reliably identify different points of the spectrum? After all, if people confuse red for green what’s the use of a colour system (and of course some people with colour blindness do have difficulty differentiating certain colours but the prevalence of this problem is low enough for us to continue using colours for many purposes).

 One way of looking at this is what’s called a kappa concordance figure. In the UK we use ICD10 as our official diagnostic system. Field trials showed the kappa figures for schizophrenia overall as a category were very good 0.77-0.84 and for bipolar, manic disorders to be 0.69-0.77. (kappa figures 0.61-0.8 are regarded as substantial agreement between separate raters). This suggests that different clinicians have a high chance of reliably agreeing between themselves what is a manic state and a psychotic state without mania.

So we can see how even if psychosis is like a multidimensional spectrum disorder and not divided into clearly separate disorders then it can still be useful to recognise different points of the spectrum if they are associated with different treatment responses and outcomes.

In short, utility without validity.

However this utility of making the diagnosis depends on how reliably the diagnosis can be made by different clinicians and whether there is sufficient difference in treatment and/or prognosis/outcome for it to be worthwhile. This needs to be made for each diagnosis.

Also, within this psychosis spectrum many people don’t come close to either archetype (equivalent to yellow or green) so assumptions of treatment response and prognosis are less likely to apply to them.

At this point we start to get “how-cannery”, how can these broadbrush archetypes actually predict treatment response, outcomes etc? How can people with such varying content even within the same symptom (the wide variety of different types of persecutory delusions for example)  let alone multiple types of symptoms have the same range of probabilities of response to treatment and outcome? Setting aside the fact that the brain outputs are by far the most complex of any bodily organ outputs  (compare the heart which basically pumps blood), the fact is that research and clinical practice demonstrates that this is indeed the case. A hypothetical problem is solved by experience in the real world. Of course in psychiatry and general medicine also, people with the same diagnosis have different responses to treatment and outcome.

People not using the medical model often have other ways of describing problems that they find more useful to them when helping people with their problems