Self-stimulatory behavior, also known as stimming and self-stimulation, is the repetition of physical movements, sounds, or words, or the repetitive movement of objects common in individuals with developmental disabilities and most prevalent in people with autism spectrum disorders. It is also commonly seen in people with anxiety disorders such as obsessive-compulsive disorder, ADHD, and Tourette syndrome, and in people with neurological disorders or brain infections. It is considered a protective response to over-stimulation, in which people calm themselves by blocking less predictable environmental stimuli, to which they have a heightened sensitivity.Sensory processing disorder is also given as a reason by some therapists for the behavior. Another theory is that stimming is a way to relieve anxiety and other emotions.
Common stimming behaviors (sometimes called stims) include hand flapping, rocking, excessive or hard blinking, pacing, head banging, repeating noises or words, snapping fingers, and spinning objects. Stimming is almost always present in autism, but does not necessarily indicate its presence. The biggest difference between autistic and non-autistic stimming is in the type of stim and the quantity of stimming. When the need to stim or the amount of stimming interferes with normal behavior, it becomes diagnosable as autism, Asperger's or SPD (not recognized in the Diagnostic and Statistical Manual of Mental Disorders).
In the Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, this type of behavior is described as "stereotyped and repetitive motor mannerisms" and listed as one of the symptoms of autism. There are numerous ways to reduce or eliminate stereotypic behaviors, including providing alternative forms of stimulation and the use of medication (however, it is not clear whether medication is actually beneficial or restricts the individual from finding relief).[clarification needed]
The majority of the autistic community opposes attempts to reduce or eliminate stimming, as it is an important tool for self-regulation. Many contend that attempts to stop people from stimming are potentially abusive.[clarification needed]
Stimming can sometimes be self-injurious, such as when it involves head-banging, hand-biting, and excessive self-rubbing and scratching. However, viewed through the lens of SPD and autism, these behaviours can be seen as an adaptive response to over- and underwhelming interpretation of sensory stimuli[clarification needed]