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Stereotypic movement disorder (SMD) is the rhythmic repetition of body movements called stereotypies. These movements are usually harmless or may result in self-harm or social challenges.

SMD often starts around age 3 years. It may occur by itself or with other conditions, such as Autism Spectrum Disorder (ASD).


It is not clear what causes SMD. Some children with SMD have family members who had SMD when they were young, so there may be a genetic link for some.

SMD may also be associated with neurological conditions or brain injuries in some children. Not all children with SMD have brain injury though.

Head Injury
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Risk Factors

SMD is more common in boys.

Factors that may increase a child’s risk of SMD include:

  • Having a developmental condition, such as ASD
  • Family history of SMD


Symptoms are common in children aged 3-5 years of age, but it may last longer in some children. Stereotypic movements have the following features:

  • Affect the arms, hands, head, or entire body
  • Are rhythmic
  • Do not change over time
  • Can be subtle or disrupting
  • Stop when a child’s focus changes

Symptoms may include:

  • Thumb sucking
  • Biting one’s nails, lips, hands or other body parts
  • Hair twisting
  • Rocking
  • Teeth clenching or grinding
  • Banging the head on objects
  • Nodding
  • Hand or arm flapping
  • Waving
  • Wiggling one’s fingers or opening and closing the hands


You will be asked about your child’s symptoms and medical history. Understanding the movements, what starts them, and what makes them stop will help the doctor to determine if it is SMD or other disorders that cause similar movements. A physical exam will be done. Psychological testing will also be done.


Talk with the doctor about the best treatment plan. In some cases, SMD fades over time. Minor movements that do not cause problems may not need treatment. Movements that impact social function or cause self-harm will need to be treated. Options include:

Behavior Therapy

The movements are easily stopped with distraction. Therapist- or home-based behavioral therapy can help a child recognize patterns and reduce or stop movements with positive reinforcement.

Cognitive behavioral therapy (CBT) may also be used to change patterns of thinking that are unproductive and harmful. However, it may not be helpful in very young children.


There is no specific medication to treat SMD. If therapy is not effective and symptoms are severe, then medication may be chosen on a case by case basis to help symptoms that do not respond to therapy.


SMD cannot be prevented.


Family Doctor—American Academy of Family Physicians  

Healthy Children—American Academy of Pediatrics  


Canadian Pediatric Society  

Health Canada 


Disorders of childhood: Stereotypic movement disorders. website. Available at: Published February 4, 2008. Accessed July 6, 2017.

Primary (non-autistic) motor stereotypies. Johns Hopkins Medicine website. Available at: Accessed July 6, 2017.

Your child’s stereotypies. Evelina London website. Available at: Updated August 2016. Accessed July 6, 2017.

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