Intellectual & developmental disabilities

Experts look at the skills people use in daily life, often grouped into three areas. A person can find some areas harder than others, and limits often sit alongside real strengths.

The three areas

• Conceptual: language, reading, money, time and numbers
• Practical: personal care, travel, schedules, safety, using the phone and work skills
• Social: getting along with people, following rules, self-esteem, and spotting when someone is taking advantage

IDDs that affect the nervous system include cerebral palsy, Down syndrome, Fragile X syndrome and autism. These can affect learning, behavior, speech, movement and sometimes seizures.

Some IDDs affect the senses, such as reduced hearing or vision. Others involve how the body uses food and energy. Not every autistic person has an intellectual disability, and not everyone with cerebral palsy does either.

An intellectual disability is not always visible, and may happen without any physical disability. Some people are good at hiding what they find hard, which can mean they miss out on help.

Many people with intellectual disabilities do a wide range of jobs and are dependable workers.

“Person-first” language puts the person first: “person with an intellectual disability.” Many people with intellectual disabilities and their self-advocacy groups use it. Some disabled people prefer “identity-first” words, like “disabled person.”

People with IDD often find that doctors, shop staff or officials talk to the person beside them instead. This can feel hurtful and leaves them out of their own life.

Simple ways to show respect

• Give time to answer, and don’t finish their sentences
• Look at and speak to the person, not only their supporter
• Offer easy-read information or pictures
• Use clear, short sentences, without talking down
• Use their communication method, like a tablet or signs

Labels like these can hide the truth. Someone called “high-functioning” may be quietly struggling. Someone called “low-functioning” may have skills and thoughts that people never notice because they communicate differently.

“Diagnostic overshadowing” means signs of a mental health problem are wrongly put down to someone’s intellectual disability. For example, a man who has stopped eating and withdrawn might be described as “just being difficult,” when he is actually depressed.

A 2024 review found the evidence on how often this happens is mixed. Still, experts agree it is a real risk, and that health workers need training to look past the disability to the whole person.

Some people can’t easily say “I feel anxious” or “I feel hopeless.” Depression may show up as irritability, body aches or stomach complaints instead.

Changes worth noticing

• Losing interest in favorite things
• Losing skills they used to have
• Many trips to the doctor about pain with no clear cause
• New aggression, self-injury or crying
• Pulling away from people
• Seeming fearful, clingy or on edge
• Sleeping or eating much more or less

Pain or a physical illness can also cause these changes. So it’s important to check physical health with a clinical provider too.

Cognitive behavioral therapy (CBT) can help with anxiety and low mood. For autistic people, it often works best when adapted, for example by using more visual aids, clear and literal language, and topics the person cares about. A good therapist will adapt to each person’s way of communicating.

Look for a therapist who

• Has experience with IDD
• Includes a trusted supporter if the person wants
• Is open to the person’s communication style
• Works on goals the person chooses

Ideas to ask for

• A longer appointment, or the first or last slot of the day
• A quiet waiting area
• A trusted supporter in the room
• Easy-read information or pictures
• Talking directly to the person, not only to their supporter
• Using the person’s communication method, such as a tablet or signs

In the U.S., about 5,775 babies are born with Down syndrome each year. Many people with Down syndrome live happy, healthy lives. Some also have other health needs, such as heart conditions, hearing loss or sleep apnea.

Like anyone, people with Down syndrome can face anxiety, low mood or big life changes, such as leaving school, a friend moving away or a parent getting older. Down syndrome is also linked with a higher chance of being autistic.

Groups such as the National Down Syndrome Society (ndss.org) and the National Association for Down Syndrome (nads.org) offer information and support to families.

By age 40, most people with Down syndrome have brain changes linked to Alzheimer’s disease. Estimates suggest 50% or more will develop dementia due to Alzheimer’s as they age, though not everyone does.

This happens because of the extra copy of chromosome 21, not because it is passed down from a parent. Losing skills, new confusion or mood changes in an adult with Down syndrome should be checked by a clinical provider, as other health problems can cause them too.

A person may not have the words for what happened, or may fear losing support if they speak up. Distress can show in actions, like new fear of a place or person, sleep changes, or losing skills.

If someone tells you

• Don’t ask lots of leading questions
• Keep them safe, and get help
• Stay calm and thank them for telling you
• Tell them it is not their fault

Spotting when someone is taking advantage, and staying safe, are part of the everyday social skills that people with IDD can learn and practice with support.

Ideas to practice together

• Knowing it is OK to say “no”
• Naming body parts and private parts correctly
• Practicing what to do if something feels wrong
• Who your trusted people are, and how to reach them

Protection and Advocacy (P&A) agencies work in every U.S. state and territory to protect the rights of people with disabilities. There are 57 of them. They give legal support so people can make their own choices and live independently.

Supported decision-making starts from the belief that people with intellectual and developmental disabilities should keep choice and control over their lives. Trusted supporters explain things in ways the person can understand.

It is not a program. It is a process of working with the person to find where help is needed, and giving help only there.

In guardianship, a court decides a person cannot make decisions and appoints someone else to make them. In some states, a person can lose all their rights to make decisions about money, health and daily life.

Laws differ from state to state. Families can ask a Protection and Advocacy agency or a local disability organization about less restrictive options.

Self-advocacy means knowing what you need and speaking up for it. Self Advocates Becoming Empowered (SABE) is a national self-advocacy organization of people with developmental disabilities, with members from every state. It works so people with disabilities are treated as equals.

In the U.S., the Individuals with Disabilities Education Act (IDEA) gives eligible children special education and related services. In 2022–23, 7.5 million students got these services.

Not all employees with intellectual disabilities need accommodations, and many need only a few. The Job Accommodation Network (JAN) gives free, confidential advice.

Examples of accommodations

• A job coach or on-site mentor
• Checklists and written or picture instructions
• Extra training time and refreshers
• Recorded instructions
• Talking calculators or reading tools
• Timers, reminders and visual schedules

Support doesn’t stop at childhood. Adults may get help with life skills for independent living, housing, education, job coaching and training.

Skills people often build with support

• Cooking and keeping a home
• Handling money and paying bills
• Making and keeping appointments
• Using buses, trains or ride services

Being left out is a real source of stress for many people with IDD. Friendships, dating and relationships are part of a full life, and support can help people build them safely.

It’s normal to feel overwhelmed, to grieve the life you expected, and still love your child fiercely. Waiting lists, forms and meetings can wear anyone down.

What can help

• Ask for respite care so you can rest
• Connect with other parents through local chapters
• Get your own counseling if you need it
• Take turns with a partner or relative

Many parents of adult children with disabilities worry about who will support their child later in life. Planning ahead, with your loved one involved, can bring peace of mind.

Things to think about

• Local chapters of disability organizations, which can explain options
• Where your loved one would like to live
• Who could be a backup supporter
• Writing down routines, likes and dislikes

The Arc of the United States supports and advocates for people with intellectual and developmental disabilities and their families, and has done since 1950. It has hundreds of local chapters that connect people to services and support.

Use the “Find a Chapter” tool at thearc.org to find one near you.

Self Advocates Becoming Empowered (SABE) is led by people with developmental disabilities. Website: sabeusa.org.

Ways your community can help

• Hire people with IDD, and give real responsibilities
• Invite people to join in, and accept a “no” kindly
• Make clubs and sports open to all abilities
• Offer easy-read signs and menus with pictures
• Volunteer with local disability organizations