Our Story

Four Decades of Advancing IDD/MH Dual Diagnosis Care

NADD was founded on a simple but powerful belief, that people with intellectual and developmental disabilities deserve access to competent, person centered, mental health care. Tailored to their individual needs. That belief still drives everything we do.

1983

Founded with Purpose

Dr. Robert J. Fletcher founded NADD in response to a critical gap. Professionals working with individuals with IDD and co-occurring mental health needs had no dedicated forum for education, research, or advocacy. NADD was created to change that.

Young Children Patients in Willowbrook State Institution in 1973
1970s

A Field Coming Into Focus

For centuries, people with disabilities were institutionalized, segregated, and denied basic human rights and dignity. The exposés of the 1970s, including Geraldo Rivera’s landmark investigation of Willowbrook State Institution in 1973, sparked legislative reforms and a growing national conversation about the rights and needs of this population. In 1982, psychologist Steven Reiss coined the term diagnostic overshadowing, recognizing that the psychiatric needs of individuals with IDD were routinely minimized or dismissed.

1984

Building the Community

NADD hosted its first conference in Suffern, NY, drawing 400 attendees. In the decades since, NADD conferences have become a professional home for clinicians, service providers, support professionals, leader, researchers, educators, and advocates across the country and around the world. Throughout the 1990s, NADD worked to bridge the gap between parallel but disconnected mental health and IDD service systems, advocating for a whole-person approach that served the full range of each individual’s needs.

The Early Nadd Team enjoying a screening together at the theater wearing movie glasses
Early Nadd Members Discussing in 90s suites
1997

Advancing the Science

NADD Press was established to produce and distribute cutting-edge research in the field. That same year, work began on the DM-ID, a diagnostic manual developed to support more accurate diagnoses for individuals with IDD, used alongside the DSM. The DM-ID was published in 2007 and is now in its second edition, the DM-ID-2. In 2007, NADD partnered with NASDDDS and other industry leaders to develop the NADD Competency-Based Accreditation and Certification Programs.

2018

New Leadership, Continued Mission

Jeanne Farr assumed the role of Chief Executive Officer following the retirement of founder Dr. Robert Fletcher. Under her leadership, NADD has deepened its focus on professional development, best practice standards, and cross-system collaboration ensuring NADD’s work continues to empower practitioners, organizations, and families.

Jeanne Farr CEO NADD
2025 Conference NADD Award Winners
Today

Advancing the Field Together

NADD works closely with people with lived experience, families, professionals, and partner organizations to improve support for people with intellectual and developmental disabilities and co-occurring mental health needs. Through education, consultation, research, publishing, credentialing, and collaboration, we strengthen practice, inform policy, and help turn shared knowledge into meaningful change in people’s lives.

Understanding IDD/MH Dual Diagnosis

People with intellectual and developmental disabilities (IDD) can experience the full range of mental health conditions, just like anyone else. When a person with IDD also experiences a mental health condition, this is often described as a co-occurring IDD and mental health condition, or dual diagnosis. Mental health needs among people with IDD can be overlooked, misunderstood, or attributed to other conditions. NADD is committed to improving the recognition, understanding, and access to quality mental health care for people with IDD.

Intellectual disability is characterized by limitations in intellectual functioning and adaptive behavior, including conceptual, social, and practical skills, with onset during the developmental period before age 22. Developmental disabilities encompass a broader group of lifelong conditions that begin during the developmental period and result in functional limitations and support needs. People with IDD have diverse strengths, abilities, preferences, communication styles, and support needs.

Mental health conditions among people with IDD may include anxiety, depression, bipolar disorder, psychotic disorders, obsessive-compulsive and related disorders, trauma-related conditions, and others. Recognizing mental health concerns may require looking beyond traditional presentations and understanding changes in behavior, communication, mood, functioning, relationships, sleep, or daily routines. Accurate assessment requires attention to the person’s unique communication and support needs, physical health, environment, life experiences, and strengths.

NADD promotes a whole-person, person-centered approach to supporting people with IDD and co-occurring mental health conditions. This approach considers biological, psychological, social, spiritual, and environmental factors while honoring each person’s dignity, voice, preferences, and right to self-determination. Our goal is to support accurate diagnoses, evidence-informed care, meaningful relationships, community inclusion, and the opportunity for every person to live a full, healthy, fulfilling life.

Be Part of the Mission

Join a growing community of professionals, organizations, and advocates committed to advancing care for individuals with IDD and co-occurring mental health needs.

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