Intellectual Disability

Intellectual disability can manifest itself in distinct ways and at different levels. Most people who receive this diagnosis can live full and rewarding lives when they have the support of family, friends, and professionals.

Intellectual Disability (Mental Retardation): What Does It Mean?

Intellectual disability is a permanent neurological condition which develops before the age of eighteen and which manifests itself as a limitation in the normal development of both adaptive and intellectual functioning.

Adaptive Functioning vs IQ

IQ tests are employed to determine a person’s level of intelligence or their intellectual functioning.  These tests elicit responses which reveal the measurable mental capacity of the person, their ability to reason and to solve problems, as well as their ability to learn. A person who scores less than 75 on an IQ test is considered to have a limited level of intellectual functioning. A person diagnosed with an intellectual disability can have a near to normal IQ, but experience problems with their adaptive functioning.

Other tests are used to determine a person’s level of adaptive, or social functioning. The Diagnostic Adaptive Behavior Scale (DABS) which is based on Item Response Theory (IRT) and which is scored by a specially designed computer program, is commonly employed. The interpretation of the results considers cultural and other influencing factors.

These adaptive functioning tests relate primarily to learned skills that everyone needs to survive in the everyday world, and they can be divided into three groups.

  • Practical skills, like dressing, eating and performing personal hygiene routines, using public transport and understanding schedules, or using a telephone.
  • Social skills which include relationship building, a concept of self, and the capacity to follow instructions
  • Conceptual skills which involve an understanding of time and numbers, the ability to use money, and to communicate.

Rosa’s Law: PUBLIC LAW 111–256—OCT. 5, 2010

Eight years ago, Rosa’s Law passed into United States federal law. Until this time, the words “mentally retarded” and “mental retardation” were the standard terms employed in all matters relating to education, federal health, and in labor policy. The new law legally replaces these outdated terms with “intellectual disability” and “individual with an intellectual disability” in federal law.

The change in the law brought the language of U.S. federal law into line with that used by the World Health Organization and Centers for Disease Control, among others. The insertion of the new terms will take place over several years as the terminology used in documents and laws is revised and updated

The new law was hailed as an important milestone in the fight for the dignity, respect, value, acceptance, and inclusion of all people. The Special Olympics had long been advocating this change of terminology and attitude, and it was a young athlete with Down’s syndrome who inspired the passing of the law.

Rosa Marcellino and her family, from Edgewater, Maryland, launched their campaign after Rosa was described as a “retard” in her school. Her brother Nick was just eleven years old when he presented his impacting testimony at the hearing to change the terminology in Maryland State Law.  He stated, “What you call people is how you treat them. What you call my sister is how you will treat her. If you believe she’s ‘retarded,’ it invites taunting, stigma. It invites bullying and it also invites the slammed doors of being treated with respect and dignity.”

Updating Terminology

The terminology in use prior to the passing of Rosa’s law had been in effect since the 1960’s when it had replaced terms that we would now consider to be offensive and derogatory. At the beginning of the 1900’s, when the profession of psychiatry was still just developing, the term idiot was used for a person with an IQ of 25 or less, imbecile for someone who scored between 26 and 50, and moron for those with a score from 51 to 75. The process of updating terminology is a continuous one and probably, in years to come, these recently approved terms will again be changed as society becomes more embracing of people with special needs and capacities.

For the sake of clarity during this current period of transitioning terminology, the term “mental retardation” is used parenthetically for ease of understanding in this article. However, the preferred (and scientific) term for this disorder is “intellectual disability.”

Stats: How Many Suffer from this Disorder?

It is estimated by the Special Olympics Organization that in the United States there are about 6.5-million people who have an intellectual disability.  Due to the difficulty in obtaining accurate data, it is impossible to be sure exactly the number of people who suffer from this disorder, but the current estimate range is from 0.87 and 3.68 percent of children in the U.S. However, some estimates place the figure as high as 15-percent of school-age children.

What Causes Intellectual Disability (Mental Retardation)?

Down’s Syndrome

Down’s Syndrome is the most common identifiable cause of intellectual disability and all people with Down’s Syndrome have intellectual disability to some degree. This is a genetic condition caused by the presence of an extra chromosome 21 for reasons that are as yet unclear. Down’s syndrome is the cause of about 15-20-percent of cases of intellectual disability.

Fetal Alcohol Syndrome (FAS)

FAS is the most severe form of the Fetal Alcohol Spectrum Disorders and is one of the most common causes of intellectual disability. Alcohol consumption by the mother, particularly during the early stages of pregnancy prevents the correct development of the fetus’s brain.

Fragile X Syndrome

Fragile X Syndrome is the most common cause of inheritable intellectual disability. This condition is caused by changes in a single X chromosome (FMR1).

A definite cause of intellectual disability can only be determined in about 30-percent of cases. 

Signs and Symptoms of Intellectual Disability (Mental Retardation)

What are the Common Behaviors/Characteristics?

Most people with an intellectual disability experience problems in reading and have poor writing and spelling skills. They may have difficulty understanding most forms of mathematics including telling the time, using money, or reading a timetable. They may have delayed speech, and commonly have problems expressing themselves and organizing their thoughts. Most have a poor short-term memory, making learning and obeying rules difficult. Some neglect basic hygiene and healthcare. Most have trouble in forming relationships and in defining themselves.

The level of the intellectual disability determines the characteristics. People with a mild disability may only display slight problems with coordination and memory. A person suffering from a severe intellectual disability may be unable to control voluntary movements and lack the ability to communicate verbally, or, in extreme cases entirely. Some people may express themselves with physical violence, often due to frustration.

Testing: What are the Diagnostic Criteria Per the DSM 5?

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM 5) defines Intellectual Disability as follows:

“Intellectual Disability (Intellectual Developmental Disorder) is a disorder with onset during the developmental period that includes both intellectual and adaptive functioning deficits in conceptual, social, and practical domains”.

To reach this diagnosis the person must meet these three criteria:

  1. Deficits in intellectual functions, such as reasoning, problem-solving, planning, abstract thinking, judgment, academic learning and learning from experience, and practical understanding confirmed by both clinical assessment and individualized, standardized intelligence testing”.

This criterion is met by the administration and interpretation of appropriate IQ tests.

  1. Deficits in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence and social responsibility. Without ongoing support, the adaptive deficits limit functioning in one or more activities of daily life, such as communication, social participation, and independent living, and across multiple environments, such as home, school work and recreation”.

This criterion is met by using tests performed on the individual and by information provided by nearby sources. The person must show inadequate adaptive functioning in at least ONE of the three domains: conceptual, social, and practical.

  1. “Onset of intellectual and adaptive deficits during the developmental period”, which is defined as prior to eighteen years of age.

Severity levels for intellectual disability- Mild, moderate, severe, and profound.

The various levels of severity are defined by the scoring on the adaptive functioning tests, and not on IQ scores, because this is what determines the level of support required.

Intellectual Disability (Mental Retardation) and Other Conditions

Intellectual Disability (Mental Retardation) vs Acquired Brain Injury

Acquired Brain Injury is the result of damage to the brain after birth whereas intellectual disabilities normally occur during the prenatal stage, although they can sometimes occur in the perinatal and postnatal stages.  People with Acquired Brain Injury frequently retain their intellectual capacities and experience unique cognitive problems depending on the nature of the trauma.

Intellectual Disability vs Autism Spectrum Disorder

Autism Spectrum Disorder is a developmental and neurological condition which usually develops early in childhood. The causes are not known. People diagnosed with this condition are characterized by a disassociation with other people and seem to focus in on themselves and their immediate surroundings.                                                                                                                                                           

Intellectual Disability (Mental Retardation) In Adults/Children

The first signs of intellectual disability may be the slow development of normal functions such as rolling over, then sitting, crawling, and walking. Depending on the severity of the intellectual disability, with the correct support, most children can learn enough though therapy to be able to live a fulfilling life in adulthood. Some may require fulltime caring, but many may be able to live independently, hold down a job, and even have their own family.

Example Case of Intellectual Disability

“Angela” appeared to be a healthy, normal baby girl. However, her parents started to wonder if something was wrong with her as they noticed that other babies of a similar age were able to do much more than “Angela”. Her contemporaries all were able to roll over and sit up much sooner, and they were soon crawling and moving about while “Angela” remained prone. She was a happy baby and showed no signs of distress.

By the time she was two, it was clear that something was not right. “Angela” was not talking or walking. She was given a preliminary diagnosis of a mild intellectual disability with no known cause.

Thanks to this early diagnosis “Angela” began to receive therapies from a young age. An occupational therapist helped her to learn how to move her body and coordinate her limbs. A speech therapist helped her to learn to articulate and communicate. Her family loved and supported her.

“Angela” went to a school where she received a specially designed education program tailored to her needs. She participated in summer camps with similar children which helped her to develop her own personality.  She became interested in sport and started training for the Special Olympics where she found support, friendship and a huge boost to her self-esteem.

“Angela” is now eighteen.  She lives in her own apartment attached to her parent’s home where she looks after her own hygiene and basic needs. She usually eats with the family. She speaks slowly but is able to communicate clearly and she is currently receiving a training course to prepare her for a part-time position in a major food chain.

How to Deal/Coping with Intellectual Disability

Early diagnosis along with adequate and sustained treatment and support are essential if the person is to reach their full potential. Correct evaluation allows the development of an adequate program to offer an individually-tailored support program for the sufferer. Inclusion and acceptance will greatly assist the person to develop and learn. The condition is no longer regarded as a static disability but one that can improve with patience and dedication. Families with a member who has an intellectual disability can benefit from counseling with a qualified therapist who can help them to understand and accept the sufferer’s condition and learn how to support them. 

Look out for These Complications/Risk Factors

Many people with intellectual disability are subject to bullying and ridicule. This can lead to depression, anti-social behavior, or the development of a low level of self-esteem. People with this condition require a level of protection to prevent them from being mistreated or misled as they may be rather gullible.

People with intellectual disability have been shown to have a higher prevalence of associated health conditions such as anxiety disorders, heart conditions, seizures, obesity, visual impairment, and hearing loss. 

Intellectual Disability (Mental Retardation) Treatment

Possible Medications for Intellectual Disability (Mental Retardation)

Medication is not normally employed directly in the treatment of intellectual disability. However, people with this condition who exhibit aggressive behavior may benefit from the use of psychotropic medication. These can include antipsychotics, anti-anxiety drugs and anti-depressants, beta-adrenergic blockers, psychostimulant and opioid antagonists. It is estimated that between 32 and 85-percent of all patients with intellectual disability will be prescribed medication at some time. Often there are co-existing conditions which require specific medications. 

Home Remedies to help Intellectual Disability (Mental Retardation)

The best home remedy to help people with intellectual disability is a varied diet with lots of fresh fruits and vegetables to provide the necessary vitamins and minerals for correct body functioning.  Supplements of the herb Ginkgo Biloba may aid memory and reduce anxiety. Other herbs such as a tea made of Chamomile flowers can help to calm and relax.  Homeopathic remedies and alternative treatments such as acupuncture may help some sufferers. The effectiveness of any of these methods has not been clinically proven, and because of the permanent nature of this condition, they are used mainly in the treatment of symptoms, not as a cure.

Living with Intellectual Disability (Mental Retardation)

Most people with intellectual disability can live full and happy lives.  Participation in sporting activities can be very beneficial. It can promote better health in general, and provide an important boost to self-esteem, create friendships, and provide a sense of self-worth and acceptance. The unconditional love and support of the family is essential for a person with this condition to develop to their full potential.

Insurance Coverage for Intellectual Disability (Mental Retardation)

Some private insurance companies cover the ongoing costs of care for a person with intellectual disability. The health law requires that policies cover essential health benefits which include rehabilitative and habilitative services. Consult with a healthcare professional as to what financial help may be available to you and to how to obtain it.                 

How to Find a Therapist

Different types of therapists can help the sufferer of intellectual disability to improve their adaptive behavioral skills. Therapies can minimize the negative effects of the condition and maximize the person’s potential.

An Occupational Therapist

  • Can improve self-care skills such as bathing, dressing, and feeding
  • Teach purposeful activities such as employment skills
  • Improve domestic skills like cooking and cleaning
  • Encourage leisure activities such as playing games or knitting

A Speech Therapist

  • Can improve communication skills through speech articulation, vocabulary and expressive and receptive language skills
  • In the absence of speech, they can help to develop other communication skills

A Physical Therapist

  • Can help to improve mobility and self-locomotion
  • Can increase sensory integration

Consult with your healthcare team as to how to find the necessary professionals to best attend the specific needs of the sufferer.

What Should I be Looking for in an LMHP?

Research the different therapist recommendations you receive to see which of them offers the kinds of therapies that could be most beneficial to your family member with intellectual disability.  Make sure that they hold valid, current qualifications, and arrange an initial interview. With these kinds of therapies, it is vital that both the patient and the family have confidence and a sense of rapport with the chosen therapist.

Questions to Ask a Potential Therapist

  • What types of therapies do you employ?
  • What kind of progress could be expected with these therapies?
  • Would the treatment program have a set time-frame?
  • How often would therapy take place?

A diagnosis of Intellectual Disability can at first seem depressing and daunting. However, many families have discovered unexpected joys in caring for a person with special needs and the condition should be embraced with a positive attitude to create a supportive environment where the sufferer can grow and develop to their full potential.

Intellectual Disability Resources and Support Helpline

-American Association on Intellectual and Developmental Disabilities (AAIDD)
501 3rd Street, NW, Suite 200, Washington, D.C. 20001
Telephone: 202-387-1968.  Fax: 202-387-2193

-National Institute of Mental Health:

-National Alliance on Mental Health: 1-800-950-NAMI (6264) or

-National Rehabilitation Information Center:

-National Suicide Prevention Lifeline:

1-800-273-8255 available 24 hrs a day

Crisis Text Line: Text “home” to 741741

-Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline: 1-800-662-HELP (4357)


author avatar
Angel Rivera
I am a Bilingual (Spanish) Psychiatrist with a mixture of strong clinical skills including Emergency Psychiatry, Consultation Liaison, Forensic Psychiatry, Telepsychiatry and Geriatric Psychiatry training in treatment of the elderly. I have training in EMR records thus very comfortable in working with computers. I served the difficult to treat patients in challenging environments in outpatient and inpatient settings
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