A meltdown is an intense response to overwhelming circumstance, which may accompany a complete loss of behavioral control. Those of us with ASD often have difficulty expressing when we are feeling anxious, overstimulated or overwhelmed. This often activates our involuntary coping mechanism—a meltdown.
Overstimulation happens when there is simply too much external stimulus or stimuli for someone with ASD or Asperger’s to process. This often leads to an overwhelming sensation of being “flooded” with information. In an attempt to escape the stimulus we melt down and the feedback loop continues.
To the outside world this can appear to be outbursts of anger (common in adults) or a temper tantrum (usually in children).
A classic tantrum is one of the most common forms of problematic behavior in young children. In neurotypical children these tend to decrease in frequency and intensity as the child grows older. For a toddler, tantrums can be considered normal, and even as gauges for developing strength of character. Tantrums can be differentiated from meltdowns in that they are generally a part of maturing as the child learns consequences of their actions. They are often an age appropriate sign of frustration and diminish over time with good parenting and education.
Those who experience anger often explain its arousal as a result of "what has happened to them" and in most cases the described provocations occur immediately before the anger experience. An angry person usually finds the cause of their anger in an intentional, personal, and controllable aspect of another person's behavior. This is very different from overstimulation and being overwhelmed with stimuli, but to the outside world (especially those who have little understanding of ASD and Asperger’s unique differences) they often appear to be the same thing.
It is important to note that both Neurodiverse and Neurotypical people experience anger. Simply because someone is on the spectrum does not mean they are devoid of the possibility of getting angry. However, discerning the difference between sensory, information or emotional overstimulation vs anger is one key to understanding many of those with ASD and Asperger’s.