ICD 11 Takes Centre Stage

Vol 6 #2


Alan Eppel

In May of 2019 the World Health Organization adopted the eleventh edition of the International Classification of Diseases, ICD 11.  This is the first revision of ICD in 30 years and was developed with wide-ranging international collaboration, field trials and extensive scientific review. Within ICD there is a  section for psychiatric disorders,  the Clinical Descriptions and Diagnostic Guidelines for Mental and Behavioural Disorders (CDDG) which has been extensively revised (1).



A number of key principles were deemed to be essential in the development of ICD 11:


  1. The preeminence of clinical utility.
  2. The need to determine the scientific validity of the included diagnoses
  3. The need to ensure international applicability.



CDDG contains several innovations:

  1. Essential features of each disorder are identified. These are symptoms or characteristics that a clinician could expect to find in all cases of a particular diagnosis. These essential features do not constitute diagnostic criteria and do not contain arbitrary symptom counts, cut-offs or required duration. This permits some flexibility in the use of clinical judgement and allows for contextual, social and cultural considerations.


  1. Disorders are no longer grouped by age but reflect a continuous lifespan approach. The previous grouping of disorders with onset occurring in childhood and adolescence has been eliminated and these conditions have been placed in the relevant diagnostic sections. For example Separation Anxiety is now contained in the Anxiety Disorder section.


  1. Culture related factors have been incorporated to reflect their influence on the expression of clinical disorders.


  1. Dimensional approaches have been integrated with the basic categorical system. This reflects the view that most psychiatric disorders comprise of a number of interacting symptom dimensions rather than discrete categories. This change is most prominently seen in the section on personality disorders but a number of dimensional qualifiers have also been added to the section on schizophrenia and primary psychotic disorders.

In the case of schizophrenia and primary psychotic disorders, diagnostic subtypes have been relinquished in favor of a dimensional classification which is felt to be more compatible with Recovery and Rehabilitation approaches.



The sections in ICD 11 are organized along a developmental perspective. The first section is on neurodevelopmental disorders while the final section is on neurocognitive disorders. Disorders are grouped according to possible etiological and pathophysiological factors as well as shared phenomenology. Cross references are made to the relevant sections in the classification of medical disorders based on medical etiology, for example in the case of sleep disorders and dementia.


Obsessive Compulsive and Related Disorders

As with DSM-5 there has been a major regrouping in the anxiety disorders category. The new category of Obsessive Compulsive and Related Disorders has been added. This includes:

  • obsessive compulsive disorder
  • body dysmorphic disorder
  • olfactory reference disorder
  • hypochondriasis/ illness anxiety disorder
  • hoarding disorder
  • trichotillomania and excoriation disorder
  • Tourette syndrome is included with cross reference to the ICD section on diseases of the nervous system.

This regrouping of OCD recognizes that while anxiety may be the most common emotion encountered in OCD, other emotions are also intrinsic: disgust, shame, and a sense of incompleteness.  The previous prohibition against diagnosing OCD concurrent with depressive disorders has been removed.

A useful clarification has been made about obsessive beliefs when they appear to have the intensity of delusions. When these fixed beliefs are entirely consistent with the OCD context, and in the absence of other psychotic symptoms, they are defined as OCD with poor or absent insight.



As with DSM 5, PTSD IS no longer part of the anxiety disorders group but appears in a section specifically associated with severe stress. Attachment disorders of childhood have been moved to this grouping.

The section on dissociative disorders has undergone major revision and includes possession trance disorders, depersonalization and derealization disorder.



A mixed depressive and anxiety category has been moved from anxiety disorders and is now grouped with depressive and bipolar disorders. Manic episodes require the presence of increased activity or energy in addition to euphoria, irritability or expansiveness. Mixed episodes are considered indicative of bipolar 1.

New qualifiers for panic attacks, anxiety symptoms, panic and seasonal pattern can be applied to both depressive and bipolar conditions.



The anxiety disorders classification is based on the primary focus or stimulus that triggers the anxiety or physiological arousal. Generalized anxiety disorder  is not related to any particular stimulus and can be diagnosed as co-occurring with depressive disorders. Hierarchical exclusion rules have been eliminated to permit comorbid diagnosis. A qualifier for panic attacks can be combined with other anxiety and depressive disorders.

Separation anxiety disorder and selective mutism have been added to the  anxiety disorders section. Separation anxiety is most  commonly focused on a romantic  partner or child.


ICD 11 versus DSM 5

In a recent review Dan Stein remarks on some of the strengths of ICD-11. Unlike DSM , ICD material is available without cost allowing international adoption:

“ICD constructs are user-friendly and better suited for adoption by non-specialists in primary care settings across the world. From the perspective of global mental health, ICD-11 clearly represents the most viable solution for mental health practice and research in diverse settings across countries. The fact that ICD-11 is founded on a rigorous and global evidence base contributes to the confidence with which it can be endorsed” (2).

The DSM process has been subject to criticism because of competing influences and its primary focus on the US health context (3,4). This is an issue requiring further discussion by professional organizations, educators, researchers and health care services.




  1. Reed GM , Michael B. First MB, Kogan CS. Innovations and changes in the ICD-11 classification of mental, behavioural and neurodevelopmental disorders. World Psychiatry 18:1, 2019, 3-19.
  2. Stein DJ. Global mental health and psychiatric nosology: DSM-5, ICD-11, and RDoC. Braz. J. Psychiatry vol.41 no.1 São Paulo Jan./Feb. 2019 Epub Jan 17, 2019



3. Widiger TA. Changes in the Conceptualization of Personality Disorder: The DSM-5 Debacle.              Clin Soc Work J (2013) 41:163–167.


  1. Skodol AE. Personality disorder classification: stuck in neutral, how to move forward? Curr Psychiatr Rep. 2014; 16:480.
Print Friendly, PDF & Email