Reframing psychiatry of intellectual developmental disorders: from margins to mainstream, from classification to care

Over the past decade, recognition of the mental health needs of individuals with intellectual developmental disorders (IDD) has advanced significantly. These advances have transformed our understanding of etiology, enriched psychiatric practice, and increased focus on global equity. In this context, the WPA Section on Psychiatry of Intellectual and Developmental Disorders and its affiliated Working Group have maintained a strong global presence, focusing on building capacity, improving training, and promoting inclusive, person‐centred psychiatric services ¹ . We see a light at the end of a tunnel, one historically marked by neglect and inequality, now illuminated by scientific progress, ethical responsibility, and collective dedication.

For too long, individuals with IDD have been pushed to society’s margins – excluded from education and health care, subjected to lifelong institutionalization, eugenic policies, and even state‐sponsored extermination. Psychiatry, at times complicit, distanced itself by placing IDD in Axis II of the DSM frameworks. Individuals with IDD were often left out of epidemiological studies, clinical trials, public policies, and scientific research. Even the Global Burden of Disease Study limited its analysis to IDD without known aetiology, excluding established genetic conditions such as Down syndrome, perinatal injuries, and other identified causes ² . Concurrent IDD continues to be often categorized under autism in estimates of disability adjusted life years and related costs. As a result, diagnostic overshadowing and therapeutic nihilism persist within the scientific community.

Nonetheless, today, IDD plays an increasingly central role in our understanding of developmental neurobiology, behavioral phenotypes, genomics, precision medicine, and comparative clinical effectiveness research, alongside its integrated model of health, social, and other sectors in care delivery. Early intervention, lifelong care, interdisciplinary collaboration, and a renewed focus on dignity and inclusion now define the field. This shift is not just scientific and technical – it is moral. Psychiatry is returning to its roots as a healing profession, grounded in shared humanity.

The inclusion of IDD in the neurodevelopmental disorder group in DSM‐5 and ICD‐11, led by members of this Section, has been catalytic, leading to significant changes in its diagnostic criteria ³ . Notably, severity levels now rely on adaptive behaviors instead of IQ‐centric thresholds, with a tripartite model of these behaviors better reflecting key skill areas (conceptual, social and practical), which indicate individual support needs. The increased adoption of the biopsychosocial model, rooted in developmental and lifespan perspectives, has also further driven the shift from deficit‐based to strength‐based, person‐centred care ⁴ , ⁵ .

In response to global challenges – particularly in low‐resource settings – our Section and its affiliated Working Group have adopted a strategic, multifaceted approach aligned with the goals outlined in the WPA Action Plan 2023‐2026 ⁶ , ⁷ , ⁸ . The initiatives described below show our effort to strengthen global capacity and promote equitable care.

Edited by Section officers, the Textbook of Psychiatry of Intellectual Disability and Autism Spectrum Disorder ⁹ is a volume with 43 chapters written by 116 leading specialists. It is the most comprehensive single resource on psychiatric comorbidity in IDD and low‐functioning autism spectrum disorder to date, offering detailed guidance across etiology, assessment, treatment (including behavioral, pharmacological and psychosocial approaches), and prognosis. It has helped shift the field toward an integrated and evidence‐informed framework for psychiatric care in these conditions, signalling significant progress aligned with the objectives of the WPA and the World Health Organization (WHO).

The Section and the Working Group also developed the Global E‐Handbook on Intellectual Developmental Disorder Psychiatry, an evolving, open‐access publication now available on the WPA website, consolidating insights from individual countries across all WPA regions. Covering policy, training, service models and human rights, the handbook is a living document that fosters international collaboration and promotes knowledge equity. Active encouragement for further global contributions is especially emphasized from underrepresented regions.

To improve foundational knowledge globally, the Section and the Working Group created a free IDD Introductory Podcast available on the WPA website. Designed as a primer for clinicians and trainees, this resource provides a concise overview of IDD diagnosis, intervention principles, and ethical considerations.

A dedicated chapter in the Global E‐Handbook comprises the WPA Human Rights Statement on Mental Health in Individuals with IDD, which affirms the WPA’s stance, approved by the General Assembly, on the rights of individuals with IDD and co‐occurring mental disorders, reinforcing obligations under the United Nations Convention on the Rights of Persons with Disabilities. The statement emphasizes person‐centred care and equitable access to psychiatric services as professional responsibilities, rather than mere aspirations.

We have also established a continuing professional development resource on IDD psychiatry hosted on the WPA web platform, which includes a certification pathway suitable for both academic and clinical training. A significant revision of this resource is scheduled in the next two years to incorporate new evidence, case studies, and evolving standards of practice.

The Section and the Working Group have also actively contributed to the WHO Package of Interventions, as part of the Rehabilitation 2030 initiative. The inclusion of Module 5, which focuses on neurodevelopmental disorders, marks a milestone in integrating IDD and autism spectrum disorder into global health strategies and rehabilitation systems, particularly for resource‐limited countries ¹⁰ .

Under the WPA Specialist Corner on Advances in Science and Ethics of IDD Clinical Care, we have established educational content that links scientific advances to ethical practice in IDD psychiatry. Launched as part of the WPA Action Plan 2023‐2026, this platform will highlight the importance of culturally informed care models, with a focus on vulnerability, rights, and regional diversity.

Despite these advances, significant challenges lie ahead. Diagnostic overshadowing, service fragmentation, and marginalization persist as everyday issues in psychiatry. The ongoing neglect of individuals with borderline intellectual functioning, characterized by disproportionately high mental health burden, further emphasizes the need for training and system reform in this domain. Looking ahead, we will continue to prioritize the global key areas ¹¹ . Expanding contributions to the Global E‐Handbook will serve as a dynamic platform for international collaboration.

By increasing contributions, especially from underserved regions, we aim to better represent diverse systems and contexts in IDD psychiatry. Advancing person‐centred care remains a key priority. We seek to continue to define psychiatry’s role in promoting autonomy, dignity, and social inclusion for people with IDD. High clinical standards must be balanced with flexibility, cultural sensitivity, and respect for personal choices, as well as culturally responsive practices. Embedding ethics and human rights‐based perspectives must be integral rather than additive in mainstream psychiatric training. Specialized content needs to address evolving regional insights and highlight gaps in culturally adapted care.

The efforts of the Section and the Working Group have gained significant momentum but need to be sustained. The support of future WPA Action Plans ¹² remains essential. As psychiatrists and mental health professionals, members of the WPA now possess the frameworks, tools and global insights to challenge the historic marginalization of people with IDD. Continued investment in infrastructure, education and visibility is crucial. Psychiatry’s role in IDD care must transition from a fragmented, medicalized approach to a comprehensive, value‐based commitment to inclusion within mainstream psychiatry. With a clear vision and shared purpose, we believe that we are not only approaching the light at the end of the tunnel, but are actively heading toward it, moving from the margins to the mainstream.