Below is a summary of notable changes in the ICD-11 MMS compared to the ICD-10.
General The ICD-11 MMS features a more flexible coding structure. In the ICD-10, every code starts with a letter, followed by a two digit number (e.g. ), creating 99 slots, excluding subcategories and blocks. This proved enough for most chapters, but four are so voluminous that their categories span multiple letters: Chapter (A00–B99), Chapter (C00.0–D48.9), Chapter (S00–T98), and Chapter (V01–Y98). In the ICD-11 MMS, there is a single first character for every chapter. The codes of the first nine chapters begin with the numbers 1 to 9, while the next nineteen chapters start with the letters A to X. The letters I and O are not used, to prevent confusion with the numbers 1 and 0. The chapter character is then followed by a letter, a number, and a fourth character that starts as a number (0–9, e.g. ) and may then continue as a letter (A–Z, e.g. ). The WHO opted for a forced number as the third character to prevent the spelling of "undesirable words". In the ICD-11 MMS, this limitation no longer exists: after 0–9, the list may continue with A–Z (e.g. – ). Then, following the first character after the dot, a second character may be used in the next level of the hierarchy (e.g. – ). This level is currently the lowest appearing in the MMS. The large amount of unused coding space in the MMS allows for updates to be made without having to change the other categories, ensuring that codes remain stable.
ICD-11 CDDR Following an extensive, years-long revision process involving nearly 15,000 clinicians from 155 countries, later renamed the
ICD-11 CDDR (Clinical Descriptions and Diagnostic Requirements). The CDDR is a comprehensive diagnostic manual for identifying and measuring mental illnesses with a uniform terminology, similar to the
DSM-5. The ICD-11 CDDR was developed around the same time as the DSM-5, and the work groups of both projects regularly met to discuss their efforts. The CDDR and the DSM-5 are similar, but not identical. The ICD-11 CDDR is the successor to the ICD-10 CDDG, which was first released in 1992 and was also known as the "Blue Book".
Personality disorder The diagnostic framework for
personality disorder (PD) in the ICD-11 is an implementation of a
dimensional model of personality disorders, meaning that individuals are assessed along continuous trait dimensions, with personality disorders reflecting extreme or maladaptive variants of
traits that are continuous with normal personality functioning, and classified according to both severity of dysfunction and prominent trait domain specifiers. A personality disorder or difficulty can be specified by one or more of the following
prominent personality traits or patterns: Negative affectivity, Detachment, Dissociality, Disinhibition, and Anankastia. of scholars supported the inclusion of Gaming disorder (GD), a significant number did not. Aarseth
et al. stated that the evidence base which this decision relied upon is of low quality, that the diagnostic criteria of gaming disorder are rooted in substance use and gambling disorder even though they are not the same, that no consensus exist on the definition and assessment of GD, and that a pre-defined category would lock research in a confirmatory approach. Rooij
et al. questioned if what was called "gaming disorder" is in fact a coping strategy for underlying problems, such as
depression,
social anxiety, or
ADHD. They also asserted
moral panic, fueled by sensational media stories, and stated that the category could be
stigmatizing people who are simply engaging in a very immersive hobby. Bean
et al. wrote that the GD category caters to false stereotypes of gamers as physically unfit and socially awkward, and that most gamers have no problems balancing their expected social roles outside games with those inside. In support of the GD category, Lee
et al. agreed that there were major limitations of the existing research, but that this actually necessitates a standardized set of criteria, which would benefit studies more than self-developed instruments for evaluating problematic gaming. Saunders
et al. argued that gaming addiction should be in the ICD-11 just as much as gambling addiction and substance addiction, citing
functional neuroimaging studies which show similar brain regions being activated, and psychological studies which show similar antecedents (
risk factors). Király and Demetrovics did not believe that a GD category would lock research into a confirmatory approach, noting that the ICD is regularly revised and characterized by permanent change. They wrote that moral panic around gamers does indeed exist, but that this is not caused by a formal diagnosis. Rumpf
et al. noted that stigmatization is a risk not specific to GD alone. They agreed that GD could be a coping strategy for an underlying disorder, but that in this debate, "
comorbidity is more often the rule than the exception". For example, a person can have an
alcohol dependence due to
PTSD. In clinical practice,
both disorders need to be diagnosed and treated. Rumpf
et al. also warned that the lack of a GD category might jeopardize insurance reimbursement of treatments. The
DSM-5 (2013) features a similar category called Internet Gaming Disorder (IGD). However, due to the controversy over its definition and inclusion, it is not included in its main body of mental diagnoses, but in the additional chapter "Conditions for Further Study". Disorders in this chapter are meant to encourage research and are not intended for clinical use.
Burn-out In May 2019, a number of media incorrectly reported that
burn-out was newly added to the ICD-11. In reality, burn-out is also in the ICD-10 (), albeit with a short, one-sentence definition only. The ICD-11 features a longer summary, and specifically notes that the category should only be used in an occupational context. Furthermore, it should only be applied when
mood disorders (), Disorders specifically associated with stress (), and
Anxiety or fear-related disorders () have been ruled out. As with the ICD-10, burn-out is not in the mental disorders chapter of the ICD-11, but in the chapter "Factors influencing health status or contact with health services", where it is coded . In response to media attention over its inclusion, the WHO emphasized that the ICD-11 does not define burn-out as a mental disorder or a disease, but as an occupational phenomenon that undermines a person's well-being in the workplace.
Sexual health Conditions related to sexual health is a new chapter in the ICD-11. The WHO decided to put the sexual disorders in a separate chapter due to "the outdated
mind/body split". A number of ICD-10 categories, including sex disorders, were based on a
Cartesian separation of "organic" (physical) and "non-organic" (mental) conditions. As such, the sexual dysfunctions that were considered non-organic were included in the mental disorder chapter, while those that were considered organic were for the most part listed in the chapter on diseases of the genitourinary system. In the ICD-11, the brain and the body
are seen as an integrate whole, with sexual dysfunctions considered to involve an interaction between physical and psychological factors. Thus, the organic/non-organic distinction was abolished.
Sexual dysfunctions Regarding general sexual dysfunction, the ICD-10 has three main categories:
Lack or loss of sexual desire (),
Sexual aversion and lack of sexual enjoyment (), and
Failure of genital response (). The ICD-11 replaces these with two main categories:
Hypoactive sexual desire dysfunction () and
Sexual arousal dysfunction (). The latter has two subcategories:
Female sexual arousal dysfunction () and
Male erectile dysfunction (). The difference between Hypoactive sexual desire dysfunction and Sexual arousal dysfunction is that in the former, there is a reduced or absent desire for sexual activity. In the latter, there is insufficient physical and emotional response to sexual activity, even though there still is a
desire to engage in satisfying sex. The WHO acknowledged that there is an overlap between desire and arousal, but they are not the same. Management should focus on their distinct features. The ICD-10 contains the categories
Vaginismus (), Nonorganic vaginismus (),
Dyspareunia (), and Nonorganic dyspareunia (). As the WHO aimed to steer away from the aforementioned "outdated mind/body split", the organic and nonorganic disorders were merged. Vaginismus has been reclassified as
Sexual pain-penetration disorder (). Dyspareunia () has been retained. A related condition is
Vulvodynia, which is in the ICD-9 (), but not in the ICD-10. It has been re-added to the ICD-11 (). Kraus
et al. noted that several people self-identify as "sex addicts", but on closer examination do not actually exhibit the clinical characteristics of a sexual disorder, although they may have other mental health problems, such as anxiety or depression. Experiencing shame and guilt about sex is not a reliable indicator of a sex disorder, Kraus
et al. stated. Nonetheless, it was ultimately decided to place the disorder in the Impulse control disorders group. Kraus
et al. wrote that, for the ICD-11, "a relatively conservative position has been recommended, recognizing that we do not yet have definitive information on whether the processes involved in the development and maintenance of [CSBD] are equivalent to those observed in substance use disorders, gambling and gaming". In the 2000s and 2010s, this notion became increasingly challenged, as the idea of viewing transgender people as having a mental disorder was believed by some to be stigmatizing. It has been suggested that distress and dysfunction among transgender people should be more appropriately viewed as the result of social rejection, discrimination, and violence toward individuals with
gender variant appearance and behavior. Studies have shown transgender people to be at higher risk of developing mental health problems than other populations, but that health services aimed at transgender people are often insufficient or nonexistent. Since an official ICD code is usually needed to gain access to and reimbursement for
gender-affirming care, the WHO found it ill-advised to remove transgender health from the ICD-11 altogether. It was therefore decided to transpose the concept from the mental disorders chapter to the new sexual health chapter. Also, the ICD-11 codes are more closely in line with the WHO's Global Antimicrobial Resistance Surveillance System (GLASS).
Traditional medicine "Supplementary Chapter Traditional Medicine Conditions" is an additional chapter in the ICD-11, featuring concepts that are considered part of
traditional medicine (TM). It initially consisted of one module, TM1. This module contains concepts that originated in
traditional Chinese medicine (TCM), also having long histories of development and use in Japan (
Kampo), Korea (
TKM), and Vietnam (
TVM). In February 2025, a second module was added, TM2. This module features concepts related to
Ayurveda,
Siddha, and
Unani. A third module, covering
homeopathy, is planned, as well as a fourth module covering "other TM systems with independent diagnostic conditions". , TM3 and TM4 have yet to be released. Medical procedures that are labeled "traditional" are used all over the world. A 2008 survey by the WHO found that, in some Asian and African countries, as much as 80% of the population rely on traditional medicine for primary health care. In many developed countries, 70% to 80% of the population had used a form of alternative medicine at some point, such as
acupuncture. Even though a number of countries created national classifications of TM, an international standardized system was missing. This complicated
data collection, making it more difficult for the WHO to comprehensively monitor the usage, safety, efficacy, and costs of TM-practices. During the 1970s, TM became a topic of increasing interest in Europe and North America. On 19 May 1977, the WHO passed a resolution approving the initiation of TM-related training and research, which is considered the official beginning of the WHO's endorsement of TM. The
declaration of Alma-Ata in 1978 mentioned the role of traditional practitioners in health care. In 1984, the WHO released the first version of the
Standard Acupuncture Nomenclature. The
WHO Traditional Medicine Strategy 2002–2005 outlined a plan to, among other things, integrate TM with national health care systems, expand the knowledge base about TM, and enhance its safety, efficacy, and quality. The
WHO International Standard Terminologies on Traditional Medicine in the Western Pacific Region (2007), or simply IST, defines terms related to
qi,
acupuncture,
moxibustion,
cupping,
Chinese herbology, and other concepts within traditional Chinese medicine (TCM). Elaborating on the IST, the WHO developed the International Classification of Traditional Medicine (ICTM), the contents of which form Chapter 26 of the ICD-11. The decision to include TM in the ICD-11 has been criticized, because it is often alleged to be
pseudoscience.
Editorials by
Nature and
Scientific American admitted that some TM techniques and herbs have shown effectiveness or potential, but that others are pointless, or even outright harmful. They wrote that the inclusion of the TM-chapter is at odds with the scientific, evidence-based methods usually employed by the WHO. Both editorials accused the
government of China of pushing the WHO to incorporate traditional Chinese medicine, a global, billion-dollar market in which China plays a leading role. In
Forbes,
Steven Salzberg wrote: "There's no legitimate reason to use terms such as "Chinese" medicine, or American, Italian, Spanish, Indian, or [insert your favorite nationality] medicine. There's just medicine – if a treatment works, then it's medicine. If something doesn't work, then it's not medicine and we shouldn't sell it to people with false claims." The WHO has stated that the TM chapter "is neither judging nor endorsing the scientific validity of any Traditional Medicine practice", and that its inclusion is primarily intended for statistical purposes, aiding research and evaluation.
Other changes Other notable changes in the ICD-11 include: •
Stroke is now classified as a neurological disorder instead of a disease of the
circulatory system. •
Allergies are now coded under diseases of the
immune system. the model disability survey (MDS), and the
ICF. ==Footnotes==