The National Institute for Mental Health (NIMH) is an American institution leading research into mental illnesses. Recently Dr Thomas Insel, Director of NIMH wrote an article on his blog about the future research direction for NIMH. Dr Insel’s wrote about the reliability and validity of diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders – the American Diagnostic Manual. The comments have been read and disseminated on a number of sites (e.g here, here, here, here and here). Before taking a closer look at these comments there is some benefit in looking more closely at reliability and validity.
Reliability of Diagnostic Systems
When we talk about reliability of diagnostic systems we are referring to the consistency of that diagnostic system. Reliability is a little bit more complicated than that though and there are several subtypes. The most commonly used form of reliability is inter-rater reliability. Suppose two people use the same rating instrument to rate the same person with the same presentation. If their scores correlate well then there is a high inter-rater reliability. Conversely if their scores do not correlate well then there is a low inter-rater reliability. Having a high inter-rater reliability for a diagnostic system is a good thing to have as a general rule.
Validity in Diagnostic Systems
We can have a high inter-rater reliability for a diagnostic system but the next question we need to ask is whether it really means anything. This is the issue of validity. We can give raters very detailed instructions on how to take several measures during an assessment. The raters can do this repeatedly and the measures can match up very well between the raters. At the end of the process, although the raters have done well to match the ratings of the other rater, if the ratings don’t map onto a valid construct there is little practical benefit from their efforts.
When we talk about mental illnesses, we want to make sure that these illnesses have construct validity (as with reliability there are several types of validity). In other words do the diagnostic criteria represent the phenomenon of interest. If raters measured the height and weight of subjects they might have a high inter-rater reliability but the results wouldn’t necessarily have much to do with Depression by themselves. The rating instruments should be relevant to the core features of the construct of interest.
Taking a Closer Look at the NIMH Article
The NIMH article begins with an introduction to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). There is a look at reliability as a particular strength. Following this there is a look at validity and a comparison of mental illnesses with other types of illness. The article covers the Research Domain Criteria (RDoC) Project, an ambitious project which aims to redefine mental illness along biological routes. The NIMH strategy is described as having these main assumptions and approaches
1. A diagnosis-independent approach to exploring symptoms and biology. However researchers will also take diagnostic entities and look at subdivisions or consider several groups of diagnostic categories together.
2. Analysis will focus on functional domains
3. Cognition, emotion and behaviour result from brain circuits and a better understanding of such circuits would facilitate the development of new and improved treatments
The major RDoC research domains are listed as
‘Negative Valence Systems
Positive Valence Systems
Systems for Social Processes
There are many interesting points in this article which hold promise for the future and which will benefit the understanding of mental illnesses. However this article should be understood in the wider context without which there is a potential for misinterpretation.
Effective Biocognitive Markers Already Exist for Several Disease in DSM-IV
To demonstrate this let us consider the DSM-IV diagnosis of Delirium – 293.0. Broadly speaking the diagnostic criteria state that Delirium involves a disturbance of consciousness, a change in cognition, that these changes happen over a short period of time and that there is evidence from multiple sources of the aetiology and that these sources include laboratory findings. Since there are many tools for effectively assessing cognition and the aetiology can be supported by laboratory findings we can see that biocognitive markers are central to this diagnosis.
Although Delirium can have a mild course with rapid improvement it can also be a serious condition. In the NICE guidelines it is stated that
‘….This can have serious consequences (such as increased risk of dementia and/or death)…‘ p.63
Delirium is a very common illness. Measuring just how common Delirium can be is complicated by the choice of rating instruments, the setting in which Delirium is assessed, the training of the assessors as well as the characteristics of the population being assessed (just as with many other illnesses). Again in the NICE guidelines on the basis of an analysis of the literature it was stated that
‘Rates of Delirium ranged from 14% (Radke 2008) to 64% (Zou 1998) in the hospital setting, 86% (Ely 2001; Ely 2001b) in the ICU setting; and 25% (Laurila 2003) in the mixed setting (hospital and nursing home wards)‘
As the NICE guidelines demonstrate there are also effective management approaches for Delirium. In summary, Delirium is a common and potentially serious condition for which there are effective management guidelines.
Given the above whenever there is a generic statement about the lack of biological/biocognitive markers for a psychiatric/ICD-10/DSM-IV diagnosis this can be challenged with reference to Delirium. Anyone making a generic statement of that nature must be able to justify this with specific reference to Delirium.
There are other examples in the Diagnostic Manual which demonstrate that biocognitive markers can be central to diagnosis.
Mind and Brain Are Inseparable When We Consider Mental Illnesses
In some discussions about diagnosis there is an apparent disconnect between mind and brain. If we move to a purely biological perspective then we lose the rich world of the mind – the inner world of conscious experience. Whether a person chooses to seek help for diagnosis, whether they understand the diagnoses that are given to them and whether they accept the treatment, or have the capacity to make these choices are all essential aspects of Psychiatry inseparable from the diagnosis in the real world.
Many illnesses are better understood from the perspective of the mind. When we tease out beliefs about the world, the role of volition and the modification of an illness by factors such as attention and transient emotional experiences we are dealing directly with the mind. Such information can be invaluable and it is difficult to see how this can or should be replaced with a simple biological marker.
The languages of mind and brain are both valid. Metaphorically speaking building a bridge between these languages appears to be more fruitful than a closure of the bridge altogether. Symptoms are used throughout medicine when diagnosing illnesses ranging from Influenza to Arthritis. Symptoms represent the language of the mind and play a key role in diagnosis when other supporting evidence such as laboratory tests are taken into consideration by the physician.
Why the Proposed NIMH Research Strategy Can be good for DSM and ICD
The proposed strategy described above has several interesting features. First of all it is no bad thing if there is a systematic attempt to deconstruct diagnosis by considering symptoms alone. If new diagnostic categories emerge then like the current diagnoses the underlying theory must withstand the scrutiny of science. Axiomatic truths will prevail and assumptions that do not stand up to close scrutiny will disappear over time. The diagnostic system will simply adapt to the scientific evidence.
With the NIMH focus on subtypes of current diagnoses, there will be a research drive to further refine current diagnoses. By looking across diagnostic categories researchers will be able to find common themes which can inform the underlying theory of illnesses and facilitate the development of new treatments. The NIMH post comes at an interesting time with the pending publication of DSM-V (see Appendix for a history of DSM-V).
Ely EW, Inouye SK, Bernard GR, Gordon S, Francis J, May L, Truman B, Speroff T, Gautam S, Margolin R, Hart RP, and Dittus R Delirium in Mechanically Ventilated Patients: Validity and Reliability of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU),JAMA: Journal of the American Medical Association,286(21):2703. (2001)
Ely EW, Margolin R, Francis J, May L, Truman B, Dittus R, Speroff T, Gautam S, Bernard GR, and Inouye SK Evaluation of Delirium in Critically Ill Patients: Validation of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU),Critical Care Medicine,29(7):1370. (2001b)
Radtke FM, Franck M, Schneider M, Luetz A, Seeling M, Heinz A, Wernecke KD and Spies CD Comparison of Three Scores to Screen for Delirium in the Recovery Room,British Journal of Anaesthesia,101(3):338. 2008.
Zou Y, Cole MG, Primeau FJ, McCusker J, Bellavance F,and LaPante JL. Detection and Diagnosis of Delirium in the Elderly: Psychiatrist Diagnosis, Confusion Assessment Method, or Consensus Diagnosis? International Psychogeriatrics, 10(3). 303-8. 1998.
Appendix – Recent History of Development and Debate on DSM-V
Appendix I – Other DSM-V Articles on the TAWOP Site
Appendix II – Previous DSM-V Related News Items Discussed on the TAWOP Site
The news items below are unedited and must be interpreted in terms of the subsequent developments.
DSM-V and ICD-11
The draft DSM-V criterion for a mixed depressive episode are being expanded to fit more closely with clinician’s experience and there are further details here. The new version of the World Health Organisation Classification of Disease (ICD-11) is displayed in draft version here. This is a work in progress with daily updates and it will allow people to comment from July 2011 onwards. I checked out the Mental and Behavioural Disorders section and there was just a little information there (relating to indexes for mortality) at the moment. The World Psychiatric Association have a very interesting paper on the use of the ICD-10 diagnostic system by psychiatrists. The researchers surveyed 4887 psychiatrists across the world using an internet based survey tool. The use of ICD-10 varied from 0% in Kenya and 1% in the USA to 100% in Kyrgyzstan, FYRO Macedonia and Slovenia. 71% of the psychiatrists surveyed used ICD-10 as their main diagnostic system. DSM-IV was the main diagnostic system for 23% of the psychiatrists surveyed (unweighted). 14.1% (unweighted) of the sample set ‘sometimes’ used a diagnostic system and 1.3% used the older versions of ICD-10 – ICD-9 or ICD-8 for diagnostic purposes. There is also a critical look at DSM-V at ‘Boring Old Man’ which highlights the wider debate in society.
The draft changes for DSM-V have been published by the American Psychiatric Association Draft Development Team for DSM-V here. I might have overlooked something but it looks as though it is an overview of the changes being suggested for specific conditions that are being presented.
Firstly I was interested in what amounts to a wholescale reclassification of the Dementias and related conditions into Major and Minor Neurocognitive Disorders. There are some nice ideas contained within this move including the consideration that it is not only memory which needs to be affected. However I was unclear on reading the descriptions of whether it would include the subtypes as I could find no mention of this. However it would be unusual if the various subtypes of dementia for which there is an abundance of evidence were not included as subtypes within this framework as this could be considered a step backward. Additionally I couldn’t find any mention of the term Mild Cognitive Impairment (although there are some broad similarities with minor neurocognitive disorder) and the various subtypes for which there is an emerging evidence base and which is the focus of research in the hope that a better understanding could lead to prevention or amelioration of subsequent dementia.
There were very few changes here. One suggestion was to use a catatonia specified elsewhere instead of catatonia secondary to a medical disorder.
There are some big changes in the Personality Disorders. These have been reduced from 10 to 5. One of the difficulties with the current Personality Disorder types is the diagnostic overlap. A person may fulfill the criteria for more than one type of personality disorder. There are a number of changes to the criteria which should improve reduce the number of comorbid personality disorder diagnoses. A simple Likert-scale is used for quantifying personality and personality traits and the five types are Borderline Personality Disorder, Antisocial/Psychopathic Type, Avoidant Type, Obsessive-Compulsive Type and Schizotypal Type.
There are a large number of new diagnostic labels being considered for inclusion and subsuming current labels. For instance alcohol dependence syndrome may be subsumed under Alcohol-use disorder. Cannabis withdrawal is another diagnosis being introduced. The discussions around the terms ‘addiction’ and ‘dependence’ are discussed below.
There are big changes to the diagnosis of Schizophrenia with a proposal for removing subtypes including Paranoid Schizophrenia, Disorganised and Catatonic schizophrenia. Changes are being suggested in order to bring DSM-V into closer alignment with ICD-10. Proposed changes to the criteria for Schizoaffective Disorder are meant to increase reliability. ‘Psychosis Risk Syndrome‘ is being introduced (see further discussion below) and a Catatonia Specifier is being suggested. This is apparently because catatonia is ‘often not recognised’.
Mixed anxiety and depression disorder is being introduced with criteria that avoid ambiguity. This is currently included in the appendix of DSM-IV. There is a proposal to rename Dysthymic Disorder as chronic depressive disorder. There is a proposal to replace Bipolar Disorder Most Recent Episode Mixed with a mixed specifier. There are a number of changes in the criteria of Manic Episode particularly around energy levels.
The proposal is to include Obsessive-Compulsive Disorder under a new category of ‘Anxiety and Obsessive-Compulsive Spectrum Disorders’. The changes here are further discussed in the ‘PsychBrownBag’ Blog and the ‘OCD Center of Los Angeles’ Blog below.
There is a proposed amalgamation of four conditions into ‘Complex Somatic Symptom Disorder‘ but for further discussion see the ‘OCD Center of Los Angeles’ Blog below.
The proposal is to reclassify Factitious Disorders under Somatic Symptom Disorders.
Theere is a proposal to subsume Dissociative Fugue under Disssociative Amnesia. Similarly there is a proposal to remove Dissociative Trance Disorder and integrate the criteria into the diagnosis of Dissociative Identity Disorder which has a number of other proposed changes.
There are a number of new diagnoses.
A new diagnosis of Binge-Eating Disorder is recommended (for further discussion see below). In Anorexia Nervosa there is the proposal to remove the criterion of amenorrhoea whilst in Bulimia Nervosa there are some proposed changes to the frequency of binge eating episodes and the purging criteria.
There are a number of new conditiosns (a number of which subsume other conditions) including Klein-Levin Syndrome, Primary Central Sleep Apnoea, Primary Alveolar Hypoventilation, Rapid Eye Movement Behaviour Disorder and Restless Leg Syndrome amongst others. There are a number of changes to the criteria for narcolepsy including hypocretin deficiency.
There are a large number of suggested changes including the removal of Rett’s Disorder, a number of proposed changes to the Attention Deficit and Hyperactivity Disorder criteria, the inclusion of Post-Traumatic Stress Disorder in school age children and Temper Dysregulation Disorder with Dysphoria which is further discussed below. Interestingly the wording for Separation-Anxiety Disorder may be changed so that it can be used with adults also. This is because there is evidence for an adult separation-anxiety disorder.
There is a proposal to move Adjustment Disorder to a grouping of Trauma and Stress-Related Conditions.
Discussion of the Draft DSM-V Changes Elsewhere in the Media
Links to some of the discussions elsewhere in the media are given below.
The Time article looks at a number of proposed changes for DSM-V which includes the criteria for making a diagnosis of depression,use of a continuum and the case for autistic spectrum disorders, the possible grouping of non-dependence inducing substances together with dependence inducing substances in the addiction and related disorders, reducing the number of personality disorder types and making some amendments to some of the sexual disorders. Over at PsychCentral, Dr Grohol looks at a number of features of the DSM-V draft. He is encouraging of the inclusion of Binge Eating Disorder, but is critical of the criteria used in Minor Neurocognitive Disorder, Behavioural Addictions and also Temper Dysregulation Disorder which has a narrow time period fo 6 to 10 years for diagnosis. Over at the ‘Psyche Brown Bag‘ blog, Joyce Anestis comments on the restructuring of the multiaxial system as well as the arrival of a number of new disorders including ‘hoarding disorder’, ‘olfactory reference syndrome’, ‘skin picking disorder’ and ‘psychosis risk syndrome’ amongst others and is also confused by the proposed changes to the personality disorders. The Times has a look at a number of the proposed changes including ‘sluggish cognitive tempo disorder’. Web MD has an article on the changes and features an interview with Dr First who is critical of the utility of the diagnosis of ‘Psychotic Risk Syndrome’.
Dr Dan Carlat has a discussion of the proposed criteria on his blog and seems fairly positive on these (however I would just add that there are neurobiological criteria for a number of disorders in DSM-IV/DSM-V draft e.g Hypocretin Deficiency in Narcolepsy above). He notes that Temper Dysregulation Disorder is being favoured as it would avoid a diagnosis of Bipolar Disorder in children in a number of cases. He’s in favour the use of addiction in place of dependence or abuse and also the use of the concept of Binge-Eating Disorder. The New York Times has a piece featuring interviews with several psychiatrists and 230 comments at the time of writing. Integral Options cafe has links to a number of posts including those on the NPR site. An article at the NPR website examines the limits of the checklist approach and how severity might be measured when using a dimensional approach. The Economist has a piece on the history of the diagnostic criteria but also cover some of the disputes that have taken place. ‘DSM-V and ICD-11 watch’ have some interesting links as well as a brief look at suggestions for medically unexplained symptoms. Dr Finnerty has an overview of proposed changes as well as some useful links. Mind Hacks has coverage here and here. The APA have a facebook site that interested readers can join.
Stanton Peele covers the proposed use of the term addictions in this ‘The Huffington Post’ article. The ‘Join Together‘ website features an interview with Dr Charles O’Brien who is chair of the APA’s DSM substances related disorders workgroup. He explains the distinction between dependence and addiction and the consideration of including the term addiction in DSM-V. They also discuss the possibility of collecting behavioural addictions together with alcohol and other drug related disorders.
Anxiety Disorders and OCD
Tom Corboy director of the ‘OCD Center of Los Angeles’ writes about a number of proposed changes over at the ‘OCD Center of Los Angeles’ blog. Thus Corboy discusses the suggested use of an ‘Anxiety and Obsessive Compulsive Disorder Spectrum’. Corboy is also critical of the suggestion of agaraphobia without panic disorder, in favour of moving Body Dysmorphic Disorder into the ‘Anxiety and Obsessive Compulsive Disorder Spectrum’ and adding a muscle dysmorphia variant, critical of the aggregation of 4 somatoform disorders including hypochondriasis, in favour of the relabelling of trichotillomania as ‘hair pulling disorder’ and also for the inclusion of skin picking disorder.
Over at the blog ‘Mental Incompetence and the Death Penalty‘ there is a guest post by Dr Watson. He criticises the proposed criteria for intellectual disability on the basis that there doesnt appear to be a consideration of the standard error for IQ testing meaning that there is what he describes as a ‘bright light’ cut-off point of 70 or below whereas in practice there is a group that are scored over 70 who would still be included amongst a number of criticisms.
Bipolar Disorder in Children
Over at the NPR website, there is a wider discussion of the diagnosis of Bipolar Disorder in children as well as the more recent ‘Temper Dysregulation Disorder’.
Autistic Spectrum Disorders
The Left-Brain Right-Brain blog compares the criteria in DSM-IV with those in DSM-V for autistic disorder and autistic spectrum disorders respectively and links to a number of other articles on the subject. There is another discussion of the autistic spectrum disorders proposition here. There is further coverage here and here.
Dr Dan Carlat takes a further look at the DSM-V draft proposals here. Dr Charles Parker has further coverage here and also over at the Corpus Callosum blog. There is a look at grief in the draft DSM-V proposals at Psychotherapy Brown Bag.
DSM-V and ICD-11
In the BJPsych there is an interesting article by Professor Michael First who writes about the potential for harmonisation of DSM-V and ICD-11 which is a widely discussed topic (First, 2009). There are a number of points of interest in the article and he notes that there are investigators involved with revisions of both systems which should help to contribute to attempts to harmonise both systems. The discussions around these systems will no doubt increase.
There was discussion recently of the diagnosis of Asperger syndrome being dropped from the next edition of the DSM and this will mean an expansion of the autism diagnostic category. This was originally discussed in a New York Times article (which requires (free) registration). The article features an interview with Dr Catherine Lord, who is one of 13 members of the working group on autism and Neurodevelopmental Disorders. The group are considering a number of amendments to the autism diagnosis including the addition of comorbidity that have been associated with the condition including disorders of attention and anxiety. However the suggestion regarding Asperger syndrome has not yet been ratified by the group. There have been a number of responses in the media. This article contains interviews with a doctor who runs a clinic, a parent of a child with Asperger’s syndrome and the president of a non-profit organisation for raising awareness of the condition. There is some information on the DSM-V process here.
DSM-V is due to appear in 2012. A twitter campaign has been started to petition for the inclusion of Depressive Personality Disorder in DSM-V. Professor Simon Baron-Cohen has argued against the removal of the Asperger Syndrome label in this New York Times article. Dr Anestis offers his views on this article and Baron-Cohen responds in this blog post.
Michael First. Harmonisation of ICD-11 and DSM-V: Opportunities and challenges. The British Journal of Psychiatry. 2009. 195. 382-390.
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