Shannon: What is the difference between autism and mental retardation?

Doreen: So autism and mental retardation are actually very, very different from each other. And I define both sort of from a clinical perspective. Autism is diagnosed when there are a number of different symptoms present. And these symptoms indicate there’s a pretty significant level of, let’s say, difficulty within the social area functioning. As well as the presence of certain stereotypical repetitive behaviors. So autism is only diagnosed when an individual has pretty significant social deficits and pretty significant stereotypical behaviors. And then the new version of autism you can have different severity levels to those things, and you can have language impairment or minimal language impairment or no language impairment along with it. And you can have intellectual disability or no intellectual disability.

Intellectual disability is mental retardation. And mental retardation is only defined as not scoring within the norm on standardized measures of intelligence, IQ. The intelligence measure, the IQ, intelligence quotient is a fraction which is your mental age over your chronological age times 100. That’s how you get an IQ. So if your mental age is, let’s say, five and your chronological age is five, then that fraction becomes one times 100, becomes 100. So normal IQ is 100 because our mental age and our chronological age are the same. In other words, we do things that all other people our age do. It’s the same, so whether you are 50 or five, your IQ will come out to be 100. Now, if your mental age is higher than, let’s say, your chronological age then, of course, your IQ becomes above 100. That fraction works out to make your IQ higher.

If your mental age is lower, then your IQ becomes lower than the 100. And if your mental age is lower, that means mentally you’re not doing all the things that people of the same chronological age are doing. That’s what IQ is. That’s what mental retardation is. Now, mental retardation to be very, very clear about it, only begins at scores below 85. So 100 being the normal IQ, 85 to 115 is also kind of within the norm. Anything below that starts to go into borderline and then starts going into mental retardation.

So what that means is that the individual’s actual abilities as measured on these tests, are more than one standard deviation different. More than 15 points difference than the vast majority of people. Which then starts to make you sort of a much, much smaller percentage of people. Like your lower than a very small group of people would have that level of problem, let’s say. So autism, while it can include mental retardation, doesn’t have to. And so they’re very, very different things. In fact, most people with autism don’t have mental retardation.

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