Stimming

[3] Such behaviors (also scientifically known as "stereotypies") are found to some degree in all people, but is especially intense and frequent in those with developmental disabilities, attention deficit hyperactivity disorder (ADHD) or autism.

[4] Stimming has been interpreted as a protective response to overstimulation, in which people calm themselves by blocking less predictable environmental stimuli, to which they have a heightened sensitivity.

[5] Although some forms of stimming behaviors have typically been shown to be healthy and beneficial—as they help regulate intense sensory experiences, relieve intense emotions such as anxiety, may facilitate understanding and social interactions with other autistic people, may promote pleasant emotions, and facilitate sense of security—[6][7][8][9][10] stimming is often socially stigmatized and looked down upon.

People who are neurodivergent often feel that they need to hide or decrease their repetitive behaviors, as it appears to not be socially acceptable, and often elicits an undesirable response from those who do not understand the needs or functions behind them.

[18][19] In some cases, stimming may be dangerous and physically harmful to the person doing it; for example, individuals may risk injuring themselves by forcefully banging their body parts against walls.

[31] The cause is not thoroughly understood, but experts believe stimming is likely linked to the effects of the dopamine imbalance that occurs in the brains of people with ADHD.

[32] Some potentially more negative or harmful stimming behaviors include teeth grinding, biting one's fingernails and lips, picking at one’s skin and scabs, overeating, impulsive actions, and chewing the inside of the cheeks.