When specialization creates exclusion: the dangers of a compartmentalized medical system
Drawing on real-world cases, the study highlights the harms of compartmentalized healthcare and proposes three essential reforms
International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo
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The study offers a real-world example of medical compartmentalization, where care is divided across specialized disciplines without coordination, and shows how comprehensive, integrated health care systems can improve overall well-being for patients.
view moreCredit: Professor Kiyoto Kasai from the International Research Center for Neurointelligence (WPI-IRCN), University of Tokyo, Japan.
Tokyo, Japan—Over the years, medical care has become increasingly specialized, with each discipline focusing on narrower areas of expertise. While this specialization has led to major advances and improved the quality of care, it has also resulted in the compartmentalization of healthcare. Patients with multiple conditions are often required to consult several specialists, and care is delivered in fragments rather than as a whole.
In a recent study, Professor Kiyoto Kasai from the International Research Center for Neurointelligence (WPI-IRCN), along with Dr. Yousuke Kumakura from the Department of Neuropsychiatry, Graduate School of Medicine, and Dr. Shin-ichiro Kumagaya from the Research Center for Advanced Science and Technology, all at The University of Tokyo, Japan, examined the severe consequences of this fragmentation by analyzing the collective experiences of multiple patients with a genetic disorder that causes a wide range of medical, developmental, and psychiatric conditions. This analysis draws on patients seen at the 22q11 deletion syndrome Special Clinic at the University of Tokyo Hospital, as well as participants from related surveys and interviews. The study reveals how compartmentalization led to a patient being refused care, details the debilitating effects on her life, and demonstrates how interdisciplinary care ultimately led to positive outcomes. Their findings are published in Volume 406, Issue 10,517 of the journal The Lancet on November 15, 2025.
“Medical compartmentalization occurs when clinicians become so entrenched in their specialty—with its own set of rules, rationality, and obligations—that they do not operate beyond their area of expertise. Our study reveals the ‘invisible mismatch’ that occurs when individuals with multiple, co-occurring disabilities, such as congenital heart disease, intellectual and developmental disabilities, and psychiatric symptoms, encounter medical systems that are organized into narrowly defined specialties,” says Prof. Kasai.
To illustrate this systemic failure, the researchers consolidated these patient experiences into a single representative case study named Cocoro, presented as a 22-year-old woman with chromosome 22q11.2 deletion syndrome. Her medical history includes a surgically repaired tetralogy of Fallot (a congenital heart defect), mild heart failure, skeletal malformations, autism spectrum disorder, and significant learning and sensory challenges. Despite her needs, she was placed in a regular school, where she faced persistent misunderstanding, bullying, and harassment by a teacher. The healthcare system proved similarly ill-equipped. Because of her medical complexity, particularly her congenital heart disease, multiple psychiatric and adult-care clinics refused to treat her, citing difficulties in managing conditions outside their specialty.
A pivotal change occurred when she was finally referred to a psychiatric department that practiced interdisciplinary care. There, a team of psychiatrists, psychologists, social workers, and a medical liaison conducted a comprehensive assessment and developed a coordinated care plan. With their help, Cocoro began attending a workshop for people with mental disabilities, where she formed supportive peer relationships. Her parents also found support by connecting with other families and later began offering peer support themselves. With this integrated approach, the family’s overall well-being improved, and Cocoro was able to re-engage with her hobbies.
Nevertheless, concerns remain about her access to future cardiac surgery in hospitals without psychiatric services and about the long-term sustainability of Cocoro’s care as her parents age. Her case highlights three main problems caused by compartmentalized care: care was split across medical specialties with no single team taking overall responsibility; her treatment became disjointed when she moved from children to adult health services; and the healthcare system focused only on her as a patient, while overlooking her caregivers.
To dismantle these barriers, the researchers propose three key systemic reforms. First, they call for changes in medical education to help clinicians recognize and address compartmentalization. Second, they emphasize ensuring continuity of care as patients transition from childhood to adulthood, particularly for those with complex, long-term conditions. Third, they call for wider changes to the healthcare system to remove structural obstacles, particularly for people with multiple long-term conditions who are most harmed by fragmented care.
As medical care becomes more fragmented, these cases highlight the need for policies and services to reconsider current practices and move toward more inclusive healthcare systems. As Prof. Kasai emphasizes, “The central message is the need to reconsider vertically segmented medical systems and to promote medical practice and medical education that ensure that no one is left behind.”
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The article, “Medical Compartmentalisation: A Patient with Chromosome 22q11.2 Deletion Syndrome in Japan,” was published in the journal The Lancet at DOI: 10.1016/S0140-6736(25)02267-6
Funding information
This work was supported by JSPS KAKENHI grant numbers JP21H05171 (to Kiyoto Kasai), JP21H05174 (to Kiyoto Kasai and Junko Kitanaka), JP21H05175 (to Shin-ichiro Kumagaya), and JP23H02834 (to Kiyoto Kasai); AMED grant number 20ek0109369 and JP25oa0439005h0001; UTokyo Institute for Diversity and Adaptation of Human Mind (to Kiyoto Kasai); and the International Research Center for Neurointelligence (WPI-IRCN) at The University of Tokyo Institutes for Advanced Study (to Kiyoto Kasai).
International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo
The IRCN was established at the University of Tokyo in 2017, as a research center under the WPI program to tackle the ultimate question, “How does human intelligence arise?” The IRCN aims to (1) elucidate fundamental principles of neural circuit maturation, (2) understand the emergence of psychiatric disorders underlying impaired human intelligence, and (3) drive the development of next-generation artificial intelligence based on these principles and function of multimodal neuronal connections in the brain.
Find out more at: https://ircn.jp/en/
About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Operating at institutions throughout Japan, the 18 centers that have been adopted are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site: www.jsps.go.jp/english/e-toplevel
About Professor Kiyoto Kasai from the University of Tokyo, Japan
Professor Kiyoto Kasai, M.D., Ph.D., is a Professor of Neuropsychiatry at the University of Tokyo School of Medicine, where he leads research at the Center for Brain Imaging in Health and Disease. A board-certified psychiatrist, his distinguished career includes clinical training in Japan and a visiting instructorship at Harvard Medical School. His research integrates neuroimaging and clinical psychiatry to elucidate brain pathology in disorders, such as schizophrenia, with a dedicated focus on developing early intervention and rehabilitation strategies to improve long-term patient outcomes within the community.
Journal
The Lancet
Method of Research
Case study
Subject of Research
People
Article Title
Medical Compartmentalisation: A Patient with Chromosome 22q11.2 Deletion Syndrome in Japan
