The terms “low” and “high” functioning are often used to differentiate between those who are severely impaired by their brain differences and those who seem hardly impaired at all. It is true that there are variations in how individuals with the same diagnosis move through the world.

However, the way we categorize functionality is more often than not based on the visible appearance of disability. In other words, if you don’t “look” or “sound” Autistic, you don’t need support, or if you “look” or “sound” Autistic, you probably can’t function.

The DSM-V contributes to these distinctions by classifying Autism into three levels, with Level 1 the “least severe” and Level 3 the “most severe”. To understand why this way of classifying severity is inaccurate, we have to understand the difference between a continuum and a spectrum.

A continuum is the existence of more or less of one thing along a single dimension. For example, if we think about temperature, we can feel more or less hot and the differences can be measured in discrete units (degrees).

A spectrum, on the other hand, is the existence of multiple things along multiple possible dimensions. For example, a rainbow is the distribution of the full range of all wave frequencies of light refracted through water. We can’t talk about a rainbow as “more or less green” or even “more or less colourful” or “more or less of a rainbow”.

Like wave frequencies of a rainbow, Autistic individuals and AD(H)D’ers, experience varying levels of strengths and challenges across multiple traits. A person who has relatively strong social (or masking) skills or specialized cognitive abilities (savants) may be perceived by others as high functioning. That same person may have such severe sensory sensitivities that they can’t tolerate going into a grocery store or walking outside in the rain. They may be so unable to organize themselves that they struggle to hold a job.

The opposite may also be true, where a person who lacks the ability to read and follow social cues or has motor coordination challenges – in other words, who “looks” Autistic or like they have AD(H)D – may be perceived as more severely disabled than they are and be excluded from opportunities in life.

There are better words that more accurately describe variations and that enable every neurodivergent person to access resources. Instead of trying to pin people down as low and high functioning, the neurodiversity movement refers to low and high support needs.

Neurodivergent individuals have different support needs and these support needs may vary over the life span. Once we, as a society, begin to listen to and believe how neurodivergent individuals perceive and experience reality, based on differences hard-wired into their brains and nervous systems, we may actually provide the kind and amount of support that is needed for each person for inclusion and justice.

The spectrum relates to: