Vocal stimming involves making or repeating certain sounds, like humming, as a self-soothing technique. While stimming isn’t a symptom of ADHD, it can closely resemble repetitive behaviors and fidgeting, which some people with ADHD experience.

Person with adhd humming and cracking her knuckles as stims to soothe and focusShare on Pinterest
AndreyPopov/Getty Images

Self-stimulation or “stimming” refers to self-soothing, mostly unconscious repetitive sounds or movements. Almost everyone stims: think hair twirling or nail-biting.

Vocal stimming refers to stimming focused on making or repeating certain sounds, like humming or repeating certain words or phrases.

For some, particularly those with autism spectrum disorder (ASD), stimming may be more common and harder to control.

Stimming isn’t a formally recognized symptom of ADHD, but it resembles some of the repetitive behaviors often seen with ADHD.

If your stimming does not put you at risk or cause you embarrassment, you may choose not to worry about it.

But if your stims worsen your distractedness or seem to be intensifying, having a medical professional test for coexisting conditions may ensure you get the most effective treatment.

Stimming is a common symptom of ASD, but isn’t a recognized symptom of ADHD. But that doesn’t mean people with ADHD can’t engage in stimming.

Research suggests there may be more overlap in the symptoms of ASD and ADHD than previously thought, especially when it comes to repetitive behaviors.

Other repetitive behaviors more commonly seen with ADHD include:

  • fidgeting
  • biting nails
  • biting inside of cheeks
  • foot-tapping
  • pacing
  • knuckle cracking
  • spinning
  • jumping

Experts aren’t sure why people with ADHD engage in repetitive behaviors like stimming, but there are some theories about the underlying causes and triggers.

Causes

A 2017 causal analysis found that hyperactivity, impulsivity, and inattention associated with ADHD influence repetitive behaviors or stimming in various ways:

  • Restlessness. Restlessness may lead to a decreased ability to control motor behaviors. While most folks blurt, hum, or fidget from time to time, people with ADHD have a harder time stopping once they start.
  • Sensory processing differences. If you live with ADHD, one feature of your experience may be hypersensitivity. This means that your mind can’t always discern which sound or sensation of many is important.
  • If you find yourself chewing your pen or singing while working, you may be unconsciously offering yourself the sensory input needed to stay present and grounded in your body and the task.
  • Impulsivity. Impulsivity with ADHD can make it hard to delay gratification. Most people stim because it feels good immediately. Once the habit of stimming starts, it reinforces itself.

Again, this is just one approach to thinking about ADHD and stimming. More research is needed to fully understand the relationship between them.

Triggers

Triggers for ADHD stimming may situations or tasks that tax executive functioning skills or worsen challenged impulse control, hyperactivity, and self-regulation. Some examples include:

  • boredom
  • overwhelm when coping with prioritizing tasks
  • distractions
  • poor sleep can worsen executive functioning skills
  • lack of exercise or mandatory sitting for long periods
  • fear, stress, or excitement

In some cases, stimming may be a symptom of another condition occurring alongside ADHD.

Autism spectrum disorder

Often, ADHD stimming looks similar to the repetitive verbal stims and stereotyped movements performed by people with autism spectrum disorder (ASD).

ASD is a spectrum of conditions that affect speech and nonverbal communication.

Some vocal stims associated with ASD include shrieking, humming, and echoing words or phrases from books or movies.

ADHDASD
stims cope with feelingsstims communicate feelings
differences in brain regions responsible for repetitive speech patternsdifferences in brain regions responsible for repetitive speech patterns
last longer than ADHD stims

A 2017 analysis of the relationship between ADHD and ASD found that up to 65% of children with ADHD have clinical symptoms of ASD. Treatment options for both conditions may also overlap.

One observation the analysis explores — though more research is needed — is that the condition overlap may support the theory ADHD is a mild subset of ASD.

Tourette syndrome and tic disorders

Tourette syndrome (TS) is a severe tic disorder that develops at a young age. While tics are repetitive movements that look like stims, the experience of tics is different.

ADHDTS
stims are unconscious but can be stopped and startedtics feel uncontrollable
stims can be soothing or focusingtics are unpleasant
relief is felt from doing the stimrelief is felt when they’re over
differences in the brain’s dopamine transmitters and receptors may be a factordifferences in the brain’s dopamine transmitters and receptors may be a factor

Tics usually onset with a precursor feeling, generalized or local to one body part.

While ADHD does not cause tics, one systematic review finds:

  • the brain differences may increase the chances of developing both conditions
  • 80% of folks with ADHD have a co-occurring condition
  • 7% of children with ADHD also have TS

Even if you have a mild tic disorder with ADHD, you may be directed to treat ADHD symptoms first.

Reviewers suggest that the symptoms of TD may be helped by treatments for ADHD.

Stims aren’t harmful and can be helpful to self-regulate. But if they are causing more disruption than self-soothing, there are options.

Often, the recommended prescription, behavior, and treatments for ADHD can reduce repetitive behaviors, even when co-occurring disorders are present.

Medication

Effective medications for ADHD can help with stimming behaviors. Stimulants commonly prescribed are:

If you or your doctor are worried about side effects, you might try nonstimulant medications:

Executive functioning help

Having a coach assist you with executive functioning challenges may relieve stress and remove triggers for stimming. A trained professional can help you develop skills in:

Behavioral therapy

If you’re concerned about how your stims appear or if they’re distracting, you may wish to ask about “habit reversal training.” You can learn to substitute:

  • gum chewing for hair chewing
  • toy squeezing for blurting out responses
  • stretching for jumping up at inopportune times

Lifestyle changes

You may be able to reduce stress and stimming behaviors by managing other triggers. Changes to consider include:

  • more sleep
  • planned exercise breaks
  • planned rewards for work accomplished

Self-advocacy

Living with a mental health condition may often mean self-advocating for your wellness at work, with family, or in social settings. On the job or at school, this might look like:

  • Proactively inform your boss or co-workers, teachers, or classmates you collaborate closely with that your brain uses vocal stims to focus, and it doesn’t mean you’re not listening.
  • Ask whether they find it distracting, and would lowering your volume or putting your hands beneath the table be a fair accommodation?

Stimming isn’t a recognized symptom of ADHD, but it can resemble some of the repetitive behaviors often seen with ADHD. In other cases, stimming may result for a coexisting condition, like ASD.

You may wish to consult your doctor about stimming symptoms if they worsen or if you develop tics.

But if your stims soothe you and keep you on task, you may choose simply to live with them.