Dear Editor, The 11th revision of the International Classification of Diseases and Related Health Problems (ICD-11), including the chapter on mental, behavioural and neurodevelopmental disorders, has been adopted unanimously by the 72nd World Health Assembly in Geneva on May 25, 2019. The endorsement of the new classification will not come into effect until January 1, 2022. Until that date, the Member States of the World Health Organization (WHO) will keep on using the ICD-10 for reporting data. The most significant innovations in the ICD-11 chapter, and the most important differences from the DSM-5, have been detailed elsewhere (Reed et al. 2019). Several issues debated in the process of development of the chapter - including the role of a dimensional component within a system that remains mainly based on categories, and the need for a further clinical characterization of the individual patient, in addition to the diagnosis, in order to guide the formulation of the prognosis and the management plan, have been also covered in the recent literature (Clark et al. 2017, Rebello et al. 2019, Fuss et al. 2019, Gureje et al. 2019, van Os et al. 2019, Fusar-Poli et al. 2019, Forbes et al. 2019, Gaebel et al. 2019, Patel 2019, Kotov et al. 2020, Maj et al. 2020, Sanislow et al. 2020). The training of professionals in the use of the ICD-11 chapter is now ongoing worldwide, under the coordination of a WHO International Advisory Group led by G.M. Reed. Educational courses have been conducted at the 18th and 19th World Congresses of Psychiatry (Mexico City, Mexico, September 27-30, 2018; and Lisbon, Portugal, August 21-24, 2019) (Giallonardo 2019, Pocai 2019, Perris 2020). A more comprehensive online 20-hr training course has been organized by the Naples WHO Collaborating Centre on Research and Training in Mental Health and the European Psychiatric Association from 9 to 30 April, 2021. The course has been coordinated by G.M. Reed and M. Maj, and has covered all the main sections of the ICD-11 chapter on mental disorders. W. Gaebel, M. Cloitre, M. Maj, C.S. Kogan, P. Monteleone, M. Swales, J.B. Saunders and N.A. Fineberg composed the Faculty. The live course has been attended by 120 psychiatrists, selected from almost 500 applicants, representing 78 different countries. A further group of 250 psychiatrists have had access to the course on demand. Two ICD-11 training sessions have been organized by the Psychiatric Association of Turkey within its 24th Clinical Education Symposium, held from 2 to 6 June 2021. One covered psychotic disorders and mood disorders, with the participation of W. Gaebel and M. Maj and the chairmanship of S. Vahip and C. Atbasoglu. The other dealt with trauma-related, fear-related and obsessive-compulsive disorders, with the participation of M. Cloitre and D.J. Stein and the chairmanship of R. Tukel and C. Kilic. Each session had more than 150 participants. An ICD-11 training event has been also organized by the UK Royal College of Psychiatrists from 25 to 26 May 2021. One further educational event is now going to be held by the World Psychiatric Association from 8 to 29 November 2021 (www.wpanet.org). A training course with exclusive access to the members of the WHO Global Clinical Practice Network (https://gcp.network) has been recently set up by the WHO Collaborating Centre on Mental Health at the Columbia University, in collaboration with the WHO Department of Mental Health and Substance Use. The course consists of 15 online training units, each focusing on a different disorder grouping and EDUCATIONAL ACTIVITIES RELATED TO THE ICD-11 CHAPTER ON MENTAL DISORDERS 292 Received: 13.09.2021, Accepted: 15.09.2021, Available Online Date: 30.11.2021 MD., University of Campania L. Vanvitelli, WHO Collaborating Centre for Research and Training in Mental Health, Naples, Italy. Dr. Vincenzo Giallonardo, e-mail: enzogiallo86@gmail.com https://doi.org/10.5080/u26898 taking from one to one and a half hours. Each unit provides a description of the relevant diagnostic grouping and the main innovations with respect to the ICD-10. Knowledge check questions are included to test the outcome of training. Participants have the opportunity to practice by applying diagnostic guidelines to clinical case examples. This training course is going to be available also in Spanish, and additional translations are planned. The WHO Global Clinical Practice Network now includes more than 16.000 clinicians from 159 countries (51% psychiatrists, 30% psychologists; 40% from Europe, 25% from Western Pacific, 24% from the Americas, 5% from Southeast Asia, 3% from Eastern Mediterranean, and 3% from Africa; 63% from high-income countries, 37% from middle- and low-income countries). The Network contributed significantly to the development of the ICD-11 chapter on mental disorders, in particular through its participation in the Internet field trials of the diagnostic system. It is now further serving as a catalyst for scientific and clinical research collaborations. All health professionals working in mental health or primary care are welcome to join the Network. Vincenzo GİALLONARDO REFERENCES Clark L, Cuthbert B, Lewis-Fernández R et al (2017). Three approaches to understanding and classifying mental disorder: ICD-11, DSM-5, and the National Institute of Mental Health's Research Domain Criteria (RDoC) Psychol Sci Public Interest 18:72-145. Forbes MK, Wright AGC, Markon KE et al (2019) The network approach to psychopathology: promise versus reality. World Psychiatry 18:272-3. Fusar-Poli P, Solmi M, Brondino N et al (2019) Transdiagnostic psychiatry: a systematic review. World Psychiatry 8:192-207. Fuss J, Lemay K, Stein DJ et al (2019) Public stakeholders' comments on ICD-11 chapters related to mental and sexual health. World Psychiatry 18:233-5. Giallonardo V (2019) ICD-11 sessions within the 18th World Congress of Psychiatry. 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