Intellectual Disability DSM­-5 319 (F79)


DSM-5 Category: Neurodevelopmental Disorders


Previously called Mental Retardation, Intellectual Disability refers to a disorder that starts during the developmental period (American Psychiatric Association, 2013). It consists of certain intellectual deficits and challenges handling aspects of daily life like school, work, home, social life, health, among other things. Intellectual disability (ID) is an explanatory phrase for sub standard intelligence that occurs below age eighteen, which is the developmental period.

While DSM-4 emphasized IQ scores, this is not so with DSM-5. Instead, no particular score is indicated to establish diagnosis, and the assessment is done based on the individual’s complete clinical presentation (American Psychiatric Association, 2013). The basis regarding this development was that this definition leaned more toward a conceptual rationale, and was not applicable to actual real-life cases. With the previous definition, an individual who met the cut off score could have adaptive issues in key areas of adaptive functioning which makes the individual’s actual functioning similar to that of people who have a much lower IQ score. Additionally, the previous term of mental retardation carried a huge social and affecting stigma, hence the adaptation of new terminology in DSM-5. While an estimated ten percent of children reportedly have some learning deficits, three percent have some form of intellectual disability.

According to DSM-5, there are three criteria that must be fulfilled in order for the diagnosis of intellectual disability (American Psychiatric Association, 2013).

(A) Deficits in intellectual functions, such as reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience, confirmed by both clinical assessment and individualized, standardized intelligence testing.

(B) 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, across multiple environments, such as home, school, work, and community.

(C) Onset of intellectual and adaptive deficits during the developmental period.

Symptoms of Intellectual Disability

Some physical, neurologic and facial abnormalities may be seen with children have intellectual disability. This may be a head that is larger or smaller than normal, or deformities seen with the hands or feet. Some children may exhibit signs such as seizures, failure to thrive, or an unusual urine odor. In some cases, there may be a delay seen with motor skills, and the ability to roll, sit, and stand. Symptoms are a lot more evident at a younger age, especially when severely affected. One of the first signs that parents observe are language delays, this may be both expressive and receptive language abilities. These children experience delay with using words, assembling words together, and being able to formulate full sentences.

There are significant delays with dressing, feeding, and using the toilet. Memory problems, and challenges with problem solving and logical reasoning are evident. Children with intellectual disability have slow social development, as a result of the deficits seen with language and cognitive abilities. Occasional behavioral disturbances can be seen, and may consist of inattention, hyperactivity, aggression, temper tantrums, heavy outbursts and self-injury (Gray, et al., 2011). This may be increased as result of the challenges with communication and difficulty with being able to control impulses. Additionally, comorbidities such as anxiety and depression are normal, especially from the children affected by the stigma seen with intellectual disability.

It is imperative to state that IQ or comparable standardized test scores must be part of an individual’s evaluation. In DSM-5, intellectual disability is seen as being at least about two standard deviations or greater below the population, which is approximately an IQ score of 70 or less. Again the emphasis is not specifically on meeting any cutoff score, but rather on how the particular individual presents.

Treatment of Intellectual Disability

In order to get early intervention for those diagnosed with ID, the diagnosis should occur early. Early intervention has been shown to improve outcomes.

The basis of treatment involves the creation of a complete management plan for the individual. This plan consists of input from the multi disciplinary team of providers, which includes behavioral therapists, special education teachers, language therapists, community resources, among others.

Since lack of adequate exercise and obesity are seen in ID, it is important to develop programs that encourage healthy lifestyles (Bartlo & Klein, 2011). This may require the assistance of a dietitian or adjusting certain antipsychotics that increase the risk for obesity.

Many individuals with ID experience intense bouts of pain, and it is important for this to be addressed in the treatment goal (Kankkunen, Janis, & Vehviläinen-Julkunen, 2010). This should be quick, and mild pain can be treated with NSAIDs or acetaminophen, while moderate pain can be treated with tramadol, and more severe pain with opioids. The use of written, verbal and illustrative methods of communication in addition to signs and demonstrations are beneficial for those with ID to guarantee shared understanding and improve treatment compliance.

Individuals with ID tend to react differently to benzodiazepines and it is best to treat them using the smallest dose possible at all times.

Care should be taken to explore the possibility of sexual abuse in individuals with ID. Given the low IQ levels, many may be prone to this, and this may influence the negative behaviors seen, such as heightened aggression.

Despite the known aspect of deficits seen with cognition, there is no main stay treatment. Limited research exist that show clear evidence of beneficial outcomes with medications.

Offering treatment is especially crucial in individuals with ID who also have co-occurring mental disorders. This is as a result of the increased risk of suicide attempts (Ludi, Ballard, Greenbaum, Pao, & Bridge, 2012). It is quite important to include questions for suicidal screening while evaluating individuals diagnosed with ID.

Living with Intellectual Disability

One of the problems that individuals with ID have is when they age out, and are no longer considered minors. No exceptions are made for these individuals, and those with a mild form of ID are normally competent enough to make proper legal and medical decisions. It is important that they are adequately informed. It is normally up to the physicians to make sure the patient understands the treatment involved and is able to give proper medical consent. In cases where an individual with ID is unable to have a firm understanding of the situation, then a family member may be granted a power of attorney which would allow the family member to consent on the patient’s behalf. In some cases, the ethics committees in the hospitals may be the best one to handle the more complex decisions, which may involve end of life care.

Patients with ID face great stigma within the community at large, and children may face bullying both at school and at home. While it helps that the term has changed from mental retardation to intellectual disability, the stigma remains. It is important that family members offer great support, to assist with activities of daily living as needed. This is especially true when dealing with both legal and medical matters. As individuals with ID are sometimes part of a larger vulnerable group prone to suicide attempts, communal support should be a priority. There should be consistent followup with the team, and the individual may not be able to control this with the cognitive deficits. Many individuals with ID tend to develop dementia as they get older (Nagdee, 2011).

In some cases, patients with ID also have a bigger medical condition, such as Down’s syndrome, Fragile X syndrome, or Klienfelter’s syndrome, which also require more extensive treatment. All of which should be considered when taking care of the ID patient at home, and in the school setting.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.

Bartlo, P., & Klein, P. (2011, May). Physical activity benefits and needs in adults with intellectual disabilities: systematic review of the literature. Am J Intellect Dev Disabil, 116(3), 220-32.

Gray, K., Piccinin, A., Hofer, S., Mackinnon, A., Bontempo, D., Einfeld, S., . . . Tonge, B. (2011, May-June). The longitudinal relationship between behavior and emotional disturbance in young people with intellectual disability and maternal mental health. Res Dev Disabil, 32(3), 1194-1204. Retrieved from Monash University:

Kankkunen, P., Janis, P., & Vehviläinen-Julkunen, K. (2010). Pain Assessment Among Non-Communicating Intellectually Disabled People Described by Nursing Staff. Open Nurs J, 4, 55–59.

Ludi, E., Ballard, E., Greenbaum, R., Pao, M., & Bridge, J. (2012). uicide risk in youth with intellectual disabilities: the challenges of screening. J Dev Behav Pediatr, 33, 431– 440.

Nagdee, M. (2011, July). Dementia in intellectual disability: a review of diagnostic challenges. African Journal of Psychiatry, 14, 194-199.

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