Intellectual Disabilities: Definition, Levels, Causes, Prevention & Treatment Video

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  • 0:06 Intellectual Disability
  • 0:43 Levels of Intellectual…
  • 2:53 Causes and Treatment
  • 5:18 Summary
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Lesson Transcript
Instructor: Natalie Boyd

Natalie is a teacher and holds an MA in English Education and is in progress on her PhD in psychology.

People with intellectual disabilities have low IQs and problems with daily functioning. In this lesson, we'll examine the levels of intellectual disabilities as well as the causes and treatments of them.

Intellectual Disability

Ethan is worried because his son Van isn't like other kids. Van doesn't understand many things and can't really talk very well. He's fourteen, but he seems to have the same intellectual capacity of a seven or eight year old. Van might be suffering from an intellectual disability, which used to be called mental retardation.

This is a psychological developmental disorder that is marked by a very low IQ and problems with everyday functioning like communication or taking care of oneself. It is almost always diagnosed before age 18.


Imagine that you are a psychologist and Ethan brings Van to see you. Van is a nice, well-behaved young man and he seems to be relatively happy. So, why does he need to see a psychologist?

Because intellectual disabilities fall under the category of lifespan development disorders, they are covered by the field of psychology. Remember that one of the criteria of intellectual disabilities is a low IQ. IQ is a measure of intellectual ability based on an intelligence test that is administered by a psychologist, another reason why Ethan has brought Van to see you.

The first step in diagnosing Van is to give him an intelligence test. The average IQ is 100, and to have some sort of intellectual disability, Van must score below 70. When you test him, he scores a 59, so he has an intellectual disability. But, there are different levels of disability, so now you must figure out which one Van has.

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