The World Health Organization (WHO) defines an intellectual disability as "a significantly reduced ability to understand new or complex information and to learn and apply new skills". The American Association on Intellectual and Developmental Disabilities (AAIDD)’s definition, on the other hand, is more specific and focuses on three areas: intellectual functioning or in other words, “general mental capacity, such as learning, reasoning, problem solving, and so on” where “an IQ (intelligence quotient) test score of around 70 or as high as 75 indicates a limitation in intellectual functioning”, substantial limits to a person’s adaptive behaviour, that is to say “the collection of conceptual, social, and practical skills that are learned and performed by people in their everyday lives” and, finally, the age of onset in particular whether the disability manifests itself before the age of 22.
Diagnosing an intellectual disability
An intelligence test can provide some clarity regarding the potential presence of an intellectual disability, but it can be never be used on its own to determine whether such a disability actually exists. A test of a person’s adaptive behaviour must be used in conjunction with the former to get a fully accurate picture of a person’s state. Depending on their severity, limitations to a person’s adaptive behaviour can have a strong effect on an individual’s life as they often result in a non-trivial impact on a person’s ability to live independently, work and be self-sufficient and even on their ability to communicate.
Symptoms of intellectual disabilities
A person with an intellectual disability will often present a noticeable learning disability, which is itself often the result of brain damage or dysfunction. Such a disability is usually is discovered during early childhood and will be present alongside other development delays. Nevertheless, one should be cautious in focusing on isolated symptoms to come to a conclusion too quickly and one should rather seek professional medical advice for a definite diagnosis.
Causes of intellectual disabilities
Anything which affects the development of the brain can cause an intellectual disability. This can occur at any time before, after or even during birth and also during childhood. A person’s genes, the consumption of alcohol during pregnancy, meningitis, oxygen deprivation during birth or even an accident are some of the factors that can result in an intellectual disability. Down syndrome is a common genetic disorder associated with intellectual disability.