3 Levels Of Autism: What's The Difference Between Mild, Moderate And Severe Autism?

Autism describes a fundamental and lifelong neurlogical difference, and one that remains, despite increased discussion on the subject, poorly understood by many. You may have heard about different the different levels of autism as described in the Diagnostic and Statistical Manual of Mental Disorders, or you may have read that autism can be separated into "low-functioning" and "high-functioning" sub-types.

What is the difference between mild, moderate, and severe autism, though? What do the diagnostic guidelines say, and do these levels matter a whole lot in real life? 

Levels of autism: What the DSM-5, the 'psychology bible', has to say

The diagnostic criteria for autism spectrum disorder themselves are fairly straightforward:

• "Persistent deficits in social communication and social interaction across multiple contexts" — this may refer to differences in body language, different ways of communicating with others that neurotypical people find hard to understand, and a different way of expressing or feeling emotions. 
• "Restricted, repetitive patterns of behavior, interests, or activities" — this can refer to physically repetitive movements or the repitition of sounds (called "stimming" in the autistic communities), a need for rigid routines, being really interested in a particular topic or a few, and things like wanting or needing to eat the same foods every day. 
• Symptoms have to show up in childhood, even though they may not have been recognized as autism. 
• Symptoms affect daily functioning in a negative way. 
• Another diagnosis couldn't better explain the symptoms. 

There's quite a few more "specifiers", terms that further describe any given autistic person's personal autism, such as "with" or "without" intellectual or language impairment.

The levels of autism are quite interesting:

• Level 1 autism may be called "mild autism" in layman's terms. People who wind up with this particular label will "need support" and would suffer impairments in daily life if they don't receive it, because though they can "speak in full sentences", what they decide to say may appear a bit weird to neurotypical people. Level 1 autistic people are also described as being inflexible in patterns of behavior and finding it hard to switch from one activity to the next. 
• Level 2 autism is sometimes called "moderate autism". The DSM-5 describes people who receive this diagnosis as needing significant support, and even with support in place, basically, everyone around them will easily see they're different. These people are reported to speak in simple sentences, have restricted interests, and "markedly odd" nonverbal communication (that's things like body language and tone of voice). The same kind of inflexible behavior will be present, and people with level 2 autism will find it very hard to cope with change. 
• Level 3 autism would be deemed "severe". According to the DSM-5, people with level 3 autism might barely speak a few words, which are themselves hard to understand, and social interaction with non-autistic people is a hard task indeed. People have "extreme" difficulty coping with change at this level, and their need for repetitive actions and routines means that having those disrupted can cause agony.

Rather than referring to levels, it's also common to hear talk of "low-functioning" vs "high-functioning" autism. 

Levels of autism from a less neurotypical perspective

I'd like to share something I came across a good while ago. Though I've been able to locate it on the web, I'm not quite sure of its original source. It goes something like this (shortened a bit for brevity):

"I know an autistic person who can typically make eye contact, understand body language, and understand sarcasm, while not having a lot of meltdowns and keeping their 'stims' to themselves. This person would be considered high-functioning. I also know an autistic person who gets overloaded in public places, often can't stand to be touched, go to the store alone, or switch from one activity to another. They might also forget to shower or eat. This person would be considered low-functioning. Guess what? They're both me."

If you thought that was thought-provoking, I've got something even better for you, and that's a comment I heard that held that levels of autism don't pinpoint how severely someone's autism symptoms impact the person themselves, but rather how severely they impact the neurotypical people around them. A similar spiel can be seen anytime — and this happens often — someone comments "if you hadn't mentioned it, I'd have had no idea you were autistic". That kind of comment means that the autistic person is good at "masking" and can "pass", for periods of time, as neurotypical. It's not a reflection of the quality of life of such a person, nor an indication of "how autistic" the person is. Being able to function fairly well in neurotypical social or professional circles does not mean that living in a world where most people aren't autistic is not challenging, or that the person will not break down and need to recover for days after a "successful" social interaction. 

Autistic people aren't the only ones who suggest that this classification system is no good, mind you; some researchers argue against it as well.