5.1.1 ICD and DSM

5.1.1 ICD and DSM

Working Knowledge of ICD and DSM Classification and Diagnostic Systems

  • The International Classification of Diseases (ICD) is used to classify most disorders in medicine.
  • The Diagnostic and Statistical Manual of Mental Disorders (DSM) is used to classify mental and behavioural disorders.
  • A good classification provides information about the causes of the disorder, possible prevention, clinical characteristics, natural history (the course of the disorder without intervention), and a guide to treatment and outcome.
  • ICD has been underfunded and unable to generate the same level of research data as DSM, but it has steadily improved with better descriptions and definitions.

Main differences between ICD-10 and ICD-11:

The International Classification of Diseases (ICD) is a standardized system for coding and classifying diseases and related health conditions. It is used for reporting medical diagnoses and procedures in healthcare settings around the world. The most recent version of the ICD is ICD-11, which was officially released in June 2018.

Key difference:Summary:
StructureICD-11 is organized differently than ICD-10. ICD-11 is based on an updated and more logical structure, which includes a number of new chapters and categories. This structure is intended to make it easier to navigate and use, as well as to improve the accuracy and consistency of diagnoses.
Classification of diseasesICD-11 includes a number of new categories and subcategories for diseases and health conditions that were not present in ICD-10. For example, ICD-11 includes new codes for diseases such as Internet Gaming Disorder and Hazardous Use of Gambling.
Classification of external causes of injuryClassification of external causes of injury: ICD-11 also includes new codes for external causes of injury, such as those resulting from cyberbullying and other forms of digital violence.
Flexibility and adaptabilityICD-11 has been developed to be more flexible and adaptable than ICD-10. It will allow for more frequent updates and revisions, which means it will be able to keep pace with advances in medical research and technology.
Online availabilityICD-11 is available in an electronic format and it is continuously updated, ICD-10 is only available as a print publication.

It should be noted that many countries will take some time to implement ICD-11, since it is a large undertaking for healthcare systems, And also there is a lag time of some years before the majority of data is captured using the new codes.

Main differences between ICD-11 and DSM-5:

ICD-11 (International Classification of Diseases, 11th Revision) is the most recent version of the World Health Organization’s (WHO) diagnostic classification system for diseases, injuries, and causes of death. ICD-11 was adopted by the 72nd World Health Assembly in 2019 and the WHO recommends that member countries transition to ICD-11 by January 1st, 2022.

One of the major changes in ICD-11 is the inclusion of a new chapter on traditional medicine, which recognizes the importance of traditional and complementary medicine in healthcare systems. Additionally, the classification system has been made more flexible, allowing for the capture of new information as it becomes available. For example, ICD-11 has introduced the use of post-coordination (combining multiple codes to describe a particular condition) to more accurately reflect the complexity of many modern medical conditions.

DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) is the most recent version of the American Psychiatric Association’s diagnostic classification system for mental disorders. It was released in May 2013 and is currently being used in the United States and other countries.

One of the major changes in DSM-5 is the replacement of the multiaxial classification system used in previous versions with a single “dimensional” classification. This means that all disorders are now grouped together based on their symptoms, rather than being separated into separate “axes” for different types of disorders (e.g., axis I for clinical disorders, axis II for personality disorders). The DSM-5 also introduced a new chapter on “Obsessive-compulsive and related disorders” and added specific diagnostic criteria for conditions such as autism spectrum disorder, hoarding disorder and substance-related disorders, among others.

Both the ICD-11 and DSM-5 have been met with criticism from some experts and organizations. They raised concerns about the lack of research supporting many of the new diagnoses, changes to the diagnostic criteria for certain conditions, and the potential for increased medicalization of normal human experiences.

It’s important to note that the ICD and DSM systems are used for different purposes and in different settings. The ICD is a coding system used primarily for the purposes of data collection and reporting, while the DSM is primarily used in the United States and other countries for the diagnosis and treatment of mental disorders in clinical settings.

Main Subgroups of Psychiatric Disorder in Both ICD and DSM:

  1. Organic, including symptomatic, mental disorders
  2. Psychoactive drug consumption causes mental and behavioural issues.
  3. Schizophrenia, schizotypal and delusional disorders
  4. Mood [affective] disorders
  5. Neurotic [a term now dropped], stress-related and somatoform disorders
  6. Behavioural syndromes linked to physiological disruptions and physical causes
  7. Disorders of personality and behaviour in adults
  8. Mental retardation
  9. Disorders of psychological development
  10. Behavioural and emotional illnesses that often manifest in young children and adolescents
  11. Unspecified mental disorders

Medical disorders and biological markers:

Most medical diagnoses have a biological basis that can confirm the disease. A ‘zone of rarity’ exists between health and disease more frequently, but not always.

The goal of psychiatric classification has been to identify an independent set of biological or pathophysiological markers that indicate disease presence and can thus confirm clinical impressions.

The main issue is a lack of specificity and an inadequate understanding of the fundamental biological processes involved in many mental disorders.

Because of the scarcity of independent evidence, there are far more mental disorder models than physical disorder models. Unfortunately, many different models still exist, including an anti-psychiatry one that rejects diagnosis entirely, allowing only the disease of labelling to manifest itself.

Zone of rarity:

The ‘zone of rarity,’ as defined by Robert Kendell (1968), is the gap between the features of a biological disorder with a clear diagnosis and other conditions that do not carry this diagnosis. It is also worth noting that there is no zone of rarity for many chronic medical conditions, such as osteoarthritis, Parkinson’s disease, and obstructive airway disease.

Uncertain threshold of diagnosis:

In the absence of a zone of rarity, the threshold for psychiatric diagnosis is usually arbitrary. When psychiatrists make a clinical diagnosis, they have no guidance in determining the boundary between disease and wellness. Almost all psychiatrists draw an arbitrary line between disorder and normalcy.

Reliability:

The ICD classification, on the other hand, despises clear diagnostic criteria unless they are independently validated and allow the clinician to make judgments in disorder classification. It is critical to understand that reliability does not imply that a disorder is better described or more valid in measuring what it claims to measure. It is always possible to achieve good agreement by having strict definitions of the condition in question, but its value will be equally limited if it is not properly described.

Main Differences between ICD and DSM

The International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM) are both diagnostic systems used by healthcare professionals to diagnose and classify mental and behavioural disorders. However, there are some key differences between the two:

  1. Purpose: The ICD is primarily used for mortality and morbidity statistics and to classify diseases, while the DSM is used primarily as a diagnostic tool in the United States.
  2. Origin: The ICD is developed and maintained by the World Health Organization (WHO), while the DSM is developed and published by the American Psychiatric Association (APA).
  3. Scope: The ICD has a broader scope, covering all types of diseases, while the DSM focuses primarily on mental and behavioural disorders.
  4. Classification systems: The ICD uses a multi-axial system for classification, considering multiple factors such as medical and psychological factors, while the DSM uses a categorical approach, grouping disorders into distinct categories.
  5. Criteria for diagnosis: The DSM provides specific criteria for each disorder, while the ICD provides more general guidelines.
  6. Updates: The ICD is updated every 10 years, while the DSM is updated more frequently, with the latest version (DSM-5) published in 2013.

The main argument in favour of DSM is that it produces more accurate diagnoses. This may be true, in part because operational criteria are used, but also because the classification requires far more resources and effort than ICD, which received very little funding.

The DSM system will continue to be used because the American Psychiatric Association has invested so much in it, and it is a well-resourced and diligent classification, and this remains true despite the numerous criticisms that it has received.

Diagnostic practice is still flexible, and it is unclear which of these two classifications – DSM or ICD- will ultimately prevail. None of these classification systems will be able to overcome the fundamental need for independent measures of disease, which will never happen for some mental diseases. We would be blind, dumb, and stupid in the practice of our art without a well-functioning classification system.

In summary, both the ICD and DSM have their own strengths and weaknesses, and healthcare professionals may use both systems in their diagnostic evaluations. However, the DSM is more widely used in the United States, while the ICD is used more globally (Tyrer, 2014).

References:

(1) Tyrer, P. (2014). A Comparison of DSM and ICD Classifications of Mental Disorder. Advances in Psychiatric Treatment, [online] 20(4), pp.280–285. doi:10.1192/apt.bp.113.011296.