When Does Different Become Dysfunctional?

The behaviours that define autism are all atypical in some way, but that doesn’t necessarily mean that they’re dysfunctional. So what’s the difference, how do you spot it and why is it important to know?

A duck sits between two bunnies

What does dysfunctional mean?

Let’s look at the definition of some of the words that we use to describe behaviour.

Normal or typical

These are behaviours that are common, either for an individual or amongst a group of people. There’s no standard set of normal behaviours, because it’s a relative term which varies according to the person and context.

Behaviours which are considered to be normal in one population may not be common at all in another (e.g. swearing), and those that are typical amongst a whole group of people may be uncommon for any one individual within that group (e.g. crime).

Abnormal or atypical

These are behaviours that are uncommon and not representative of either a population or a person’s usual state of being. By definition they’re not necessarily wrong or problematic, just different.


This literally means behaviour without a function… but since all behaviour has a function, in practicality it means ‘behaviour that has an unknown function’. It doesn’t include any reference to how common the behaviour is or whether it’s a problem.


These behaviours involve an impaired ability to function which causes a problem for somebody (either for the person themselves or those around them). Dysfunctional behaviours can be either typical or atypical for a person or population.

There are a few things to take away from this…

  • Normal or typical behaviours can be dysfunctional
  • Abnormal or atypical behaviours can be functional
  • Atypical does not equal dysfunctional

This is an important distinction to make, because figuring out whether a behaviour is dysfunctional or merely atypical is critical to deciding how (or whether) to intervene. Dysfunctional behaviours (no matter how common) need to be addressed because they are by definition a problem for somebody. Atypical behaviours that are not dysfunctional need only to be treated in the same way that typical behaviours automatically are – with acceptance.

So what does a dysfunctional behaviour look like?

Just as there’s no standard set of normal behaviours, there isn’t one for dysfunctional behaviours either. That’s because it’s impossible to classify a behaviour as dysfunctional without context.

The extent to which a behaviour is problematic changes between settings, people and over time.

Behaviours that start out as merely atypical can become dysfunctional, and those that are functional for one person might be dysfunctional for another. Or you might have behaviours that are functional at home but not in the classroom.

Repetitive play is not necessarily dysfunctional, for example. Neither is a lack of eye contact, stimming, hyperactivity or a need for sameness. All of these can be considered to be acceptable behaviours in some contexts, with the potential to become problematic in others.

Let’s take hand washing as an example

Typically, hands are washed as needed when they’re dirty. Washing more often than that (when they’re not dirty) is atypical – but if it’s just inconvenient or annoying, that’s not really enough of a problem to be considered dysfunctional. Washing hands so often that the skin breaks down and you can’t leave the house or perform other daily activities is a very big problem, and once it gets to this point the behaviour would be considered to be dysfunctional.

Where’s the line that separates functional from dysfunctional?

What does the phrase ‘causes a problem’ really mean? In broad terms, dysfunctional behaviours are those that:

  • Are dangerous
  • Cause distress, pain or harm to someone
  • Interfere with daily functioning
  • Prevent participation in the community
  • Stop someone from meeting basic needs
  • Stop someone from getting the help or education they need
  • Stop someone from independent living
  • Prevent the development of a functional behaviour

The bottom line

The only behaviours that need modifying are the ones that are dysfunctional, regardless of how common (or not) they might be.

Last updated 25 Nov, 2017 by Bec Oakley

Bec Oakley is an autistic writer and proud parent, with an intense passion for 80s text adventures, Twizzlers and making the world a better place for autistic people and their families.