ICD-11 vs DSM-5: Which System to Use in Poland

Two classification systems: where they came from

In mental health, two widely used systems for describing disorders operate side by side. The first is the ICD, the International Classification of Diseases, maintained by the World Health Organization, a specialised United Nations agency. Its most recent, eleventh revision is called ICD-11.

The second system is the DSM, the Diagnostic and Statistical Manual of Mental Disorders, prepared by the American Psychiatric Association. Its current, fifth edition is designated DSM-5, and its updated version is designated DSM-5-TR.

Both systems were created with the same goal in mind: to build a shared language that allows specialists to understand diagnoses in the same way, to collect comparable data and to conduct research. They differ, however, in the institution responsible, in scope, and in their original purpose.

For the patient, the differences between the systems usually have no practical significance; both are about describing the same phenomenon. For clinicians, researchers and those who manage health care, the distinction can nonetheless be important, which is why it is worth understanding.

ICD-11: a global classification covering all of medicine

The most important feature of the ICD is its global and general-medical character. ICD-11 does not cover mental health alone; it is a catalogue of diseases across the whole of medicine, from infectious diseases to cancers. Mental, behavioural and neurodevelopmental disorders constitute one of its chapters, designated as the sixth.

The ICD is created with countries of very different resources and care systems in mind. For this reason its diagnostic guidelines are prepared so as to be useful even where access to specialist investigations is limited. The classification is meant to work both in large clinical centres and in primary health care.

Detailed descriptions of mental disorders are collected in the CDDR document, the Clinical Descriptions and Diagnostic Requirements. For each disorder it provides a clinical description, the essential features, the boundaries with other entities, and information about the course and context.

The ICD also serves a statistical and administrative function. Its codes are used in medical records, in health reporting and in the billing of services. It is precisely this practical, system-wide dimension that distinguishes the ICD from a manual focused solely on psychiatry.

DSM-5: a manual focused on psychiatry

The DSM is narrower in subject matter than the ICD. It focuses solely on mental disorders and is prepared by a national professional association rather than by an international organisation. For this reason it is sometimes described as a manual that is primarily American in origin and character.

DSM-5 is particularly strongly rooted in practice and scientific research in the United States. Scientific publications from around the world often use DSM criteria, because over the years they have served as a shared point of reference for research into mental disorders.

Traditionally the DSM uses more detailed, operational diagnostic criteria, often in the form of symptom lists with defined numerical and time thresholds. Such a structure favours reproducibility in research, in which a precise, uniform definition of the study group matters.

DSM-5 does not replace the ICD in the administrative layer. Even in systems where the DSM is widely used in clinical work and research, the codes needed for reporting and billing come from the ICD classification. The two systems are therefore sometimes used side by side, each for its own purpose.

Where the two systems converge

Despite their institutional differences, ICD-11 and DSM-5 describe largely the same area and converge across many entities. Both systems distinguish depressive disorders, bipolar disorders, anxiety-related disorders, schizophrenia and other psychotic disorders, feeding and eating disorders, and disorders due to substance use.

This convergence is not accidental. Work on ICD-11 and on DSM-5 was conducted partly during the same period, and the expert teams of both systems sought to limit unnecessary divergence. The aim was harmonisation wherever possible, in order to make it easier to compare data and to transfer research findings between systems.

The two systems also share several basic principles. In both, a diagnosis requires that the symptoms cause significant distress or impairment of functioning. In both there is the concept of the boundary with normality, that is, distinguishing a disorder from a natural human reaction. In both, emphasis is placed on differential diagnosis and on ruling out other causes.

In practice, a clinician familiar with one system finds their way relatively easily in the other. For many disorders, such as recurrent depressive disorder (ICD-11 code 6A71) or obsessive-compulsive disorder (6B20), the general understanding of the entity is very similar in both systems, even if the details of the description differ.

Where the two systems differ

The most visible difference concerns the construction of the criteria. The DSM traditionally uses detailed operational criteria in the form of lists with numerical thresholds. In many places ICD-11 has deliberately moved away from this rigidity in favour of diagnostic requirements based on essential features, assessed in a more flexible way.

Differences also appear in the organisation of certain groups of disorders. The deepest concerns the personality disorders. ICD-11 has replaced the former list of separate types with a single diagnosis of personality disorder (code 6D10), described first in terms of severity and then by means of prominent traits. DSM-5 has retained, in its main part, the classic categorical personality types, placing the dimensional approach in a separate, alternative section.

There are also differences in the entities themselves. ICD-11, for example, has separated out complex post-traumatic stress disorder (code 6B41) as a distinct diagnosis alongside classic post-traumatic stress disorder (6B40), whereas DSM-5 does not distinguish this entity in that way. Differences also concern some thresholds, terminology, and the way related disorders are grouped.

Finally, the scope differs. ICD-11 covers the whole of medicine and has a built-in statistical and administrative function, which DSM-5, as a manual focused solely on psychiatry, does not provide. This means that the two systems do not directly compete but rather complement each other: one as a global reporting standard, the other as an extensive clinical and research tool.

Which system applies within the Polish health care system

Within the Polish health care system, the official point of reference is the ICD classification. It is its codes that are used in medical records, in health statistics and in the billing of services. In this respect, the answer to the question of which system to use in Poland is unambiguous: in the formal layer, the ICD applies.

It should be remembered, however, that implementing a new revision of the classification is a process spread over time. The transition from ICD-10 to ICD-11 in the health care systems of individual countries, including Poland, does not happen overnight; it requires adapting documentation and IT systems and training staff. The current formal status at any given moment is worth checking with an official source.

Regardless of the pace of administrative implementation, ICD-11 is already today the most recent and substantively applicable standard for describing disorders. Clinicians increasingly use its structure and the CDDR guidelines in understanding and describing the clinical picture, even before all reporting has been fully switched over.

DSM-5 is not an official system in Poland, but it plays an important supporting role. It is sometimes used in scientific work, in the training of specialists, and as an additional source for describing disorders. Many Polish clinicians know both systems and treat the DSM as a complement to, not a replacement for, the ICD classification.

The transition from ICD-10 to ICD-11: what is changing

For many Polish clinicians, a more practical question than ICD-11 versus DSM-5 is the comparison of ICD-11 with the earlier ICD-10 version, which for decades was the basis of diagnoses. The transition between these revisions does not consist solely of a change in numbering.

The structure has changed. ICD-11 groups disorders differently, some categories have been merged or reorganised, and certain former entities have been removed. Entirely new diagnoses have also appeared, such as complex post-traumatic stress disorder (code 6B41), prolonged grief disorder (6B42) and gaming disorder (6C51).

The approach has changed too. ICD-11 has strengthened the dimensional view, seen most clearly in personality disorder (code 6D10), where instead of the former separate types, severity and traits are assessed. In many places the classification has moved away from rigid numerical criteria in favour of flexible diagnostic requirements.

For the clinician this means a need to become familiar with the new structure and the new guidelines. For the patient the change is usually not directly noticeable, although in some cases a new diagnosis may reflect their situation better than the former, less precise category.

How the classification system affects the patient

From the perspective of a person seeking help, the choice of classification system matters far less than it might seem. Low mood, anxiety or intrusive thoughts remain the same experience regardless of whether they are described with an ICD-11 code or with DSM-5 criteria.

What genuinely affects the patient is the quality of the diagnostic process itself: a careful interview, sound differential diagnosis, an assessment of severity and functioning, and tailoring help to the specific person. Both systems are merely tools in the clinician's hands, not the factor that decides the quality of care.

What does have practical significance is consistency of recording. Because in the Polish health care system documentation is based on ICD codes, a diagnosis recorded in this system will be legible to the next specialists the patient sees. This makes for continuity of care.

If a patient encounters a reference to DSM-5, for example in a scientific publication, an educational material or an opinion drawn up in another country, this need not mean a contradiction. Most often it concerns the same condition described in another, parallel system. In case of doubt, it is best to ask the treating specialist for an explanation.

Which system to choose in study and practice

For students and those learning about mental health in Poland, the natural starting point is ICD-11, because it is the formal standard of the national health care system. Knowing the structure of Chapter 6 and the logic of the CDDR guidelines is the foundation of orientation in ICD-11 diagnostics.

Familiarity with DSM-5 nonetheless remains a valuable complement. Many scientific studies use DSM criteria, so an awareness of the differences between the systems makes it easier to read the literature critically and to compare findings. For those planning scientific work, this diagnostic bilingualism is in fact necessary.

In everyday clinical practice in Poland, the leading tool is the ICD classification, and DSM-5 is sometimes used in a supporting role. Many clinicians deliberately use both, treating them not as competing dogmas but as two views of the same area of knowledge.

Regardless of the choice, the same principle of caution applies. No classification system, neither ICD-11 nor DSM-5, is a tool for self-diagnosing disorders. Both are intended for trained specialists. Educational materials help one to understand how mental health is thought about, but a diagnosis is always made by a qualified clinician.

Summary: ICD-11 as the standard, DSM-5 as a complement

ICD-11 and DSM-5 are two mature, largely convergent systems for describing mental disorders. They differ in the institution responsible, in scope, and in the construction of their criteria, but they share the same goal: to organise knowledge and to create a shared language for clinicians and researchers.

Within the Polish health care system, the official point of reference is the ICD classification, and its most recent revision is ICD-11. It is in this system that medical records and reporting are maintained, which is why for practice in Poland it is the leading system.

DSM-5 is not an official system in Poland, but it retains value as a supporting tool in study, research and training. Knowing both systems makes it possible to move freely both in Polish practice and in the international literature.

The most important conclusion, however, is simple: the quality of care is decided not by the system label, but by the soundness of the diagnostic process. ICD-11 diagnostics provides an organised map of disorders, and responsibility for the diagnosis and for further management always rests with a qualified specialist.

Frequently asked questions