High functioning people are more likely to appear typical (until some event or conversation makes their autism more obvious). Low functioning people are less likely to be included in typical classes or activities and are more likely to be in a "substantially separate" academic settings.

People with autism are often described as being "high functioning" or "low functioning," but there are no such official diagnoses. In fact, now that Asperger syndrome, PDD-NOS, and autistic disorder have been removed from the DSM (diagnostic manual) there is only one general category called autism spectrum disorder.

While there are now three levels of autism described in the DSM-5 (Levels 1, 2, and 3), many people use the terms high and low functioning, as they are less clinical. The problem is that the difference between high and low functioning autism can, in many cases, be based on the personal perspectives of a parent, practitioner, or teacher.

Despite problems inherent in the terms high and low functioning autism, they are in common use, usually by people who are not autistic. And they are used to describe the degree to which someone on the spectrum is (or appears to be) like those people who are NOT on the spectrum.

In other words, autistic people who are or appear to be closer to "normal" are seen to be high functioning. Thus, for example:

• High functioning people use spoken language to communicate. Low functioning people are more likely to use technology or picture boards and may have limited or no spoken language.
• High functioning people are more likely to be able to manage the expectations of an academic setting. This is often a result of having a better handle on spoken language and a greater awareness of the expectations of others.
• High functioning people are usually more aware of social conventions. For example, they are more likely to use tools and utensils typically, greet others appropriately, etc.
• Low functioning people generally look and sound quite different from their typical peers. In other words, their disability is more visually and aurally obvious to the casual observer. High functioning people are more likely to appear typical (until some event or conversation makes their autism more obvious).
• Low functioning people are less likely to be included in typical classes or activities and are more likely to be in a "substantially separate" academic settings. High functioning people are more likely to be included, with or without support, in general classrooms and out-of-school programs.

All these distinctions, however, are artificial, and they are by no means absolute. That's because autistic people behave differently in different situations, and every individual has a range of strengths and challenges.

While it is handy to describe autistic people based on their similarity to typical people, such descriptions can be misleading. That is because low functioning people may be successful in situations where high functioning people are not, and vice versa.

For example, the "high functioning" person who appears "normal" (or even exceptional) in a secondary school classroom may find it impossible to function at a party. Meanwhile, the "low functioning" person who cannot use spoken language to chat may be more than capable of leading a conversation online.

Some typical challenges are:

Social Interaction:
• Isolated but not worried about it
• Tension, distress: Trying to cope
• Lack of strategies to make friends
• Difficult to pick up social cues
• Behave in a socially inappropriate way

Social Communication:
• Language – Perfect but formal, pendant.
• Voice – Lack of impression; tones of other voices.
• Problems with interpreting body language
• Understands others literally
• Fails to grasp implied meanings

Social Imagination:
• Flexibility of thought
• All-absorbing interest.
• Certain routines
• Limited in thinking and flexibility
• Problems in transferring skills

Motor Clumsiness:
• Awkward movements
• Organisational problems
• Hard to write and draw neatly
• Unfinished tasks