Tics, stims and stereotypies:
Differentiating Tourette's, Autism spectrum disorders, and Stereotypic Movement Disorder
"Not all that tics is Tourette's"
There are many secondary causes of tics, which is also referred to as "tourettism." These include such diverse conditions as autism, mental retardation, head trauma, stroke, Asperger's, carbon monoxide poisoning, Sydenham's Chorea, and many other conditions.
Further, there are numerous conditions besides those on the spectrum of tic disorders (transient tics, chronic tics, and Tourette's disorder) which include tics as a feature of the condition. When attempting to sort out the etiology of stereotyped movements or tics in childhood, it is helpful to be aware that "not all that tics is Tourette syndrome."
Two common conditions of childhood which are often confused with Tourette Syndrome, because of the stereotyped movements, are Stereotypic Movement Disorder, and conditions on the autism spectrum. Sorting out the similarities and differences between tics, stims and stereotypies if hard even for trained professionals, and the confusion results in a number of misdiagnoses.
The information contained here is to help parents become informed and work with their medical professionals to help sort out and differentiate between the diagnoses of tic disorders, autism spectrum disorders, and Stereotypic Movement Disorder, and to understand the similarities and differences between tics, stims, and stereotypies.
The diagnostic criterion for Tourette's disorder rule out other medical causes of tics in order to confer a TS diagnosis.
There are numerous causes of secondary tics (also referred to as "tourettism"), other than primary, inherited Tourette Syndrome.
Stereotypic Movement Disorder is another condition which may easily be confused with Tourette's. Roger Freeman, M.D. of the Neuropsychiatry Clinic at British Columbia Children's Hospital, Vancouver discusses Stereotypic Movement Disorder here:
"Stereotypic Movement Disorder can be confused with tics and TS. SMD is an official DSM-IV diagnosis, but it's rarely made. ... Repetitive movements usually start before age 2, and consist of intense patterns (like hand-flapping, pacing, running, bouncing, with or without vocalizations and facial grimacing) in longer runs than tics (can be 10-30 minutes). This can be stimulated by excitement or rarely boredom. When older, they often say they like it, it's fun, they have to do it before they do something else, and that it stimulates their fantasies, yet they can usually be easily called out of it. It often looks very odd. They typically shape their patterns later so that the movements are done in private or within the family. The main problem is that if you're not familiar with it, you're likely to think it's an autistic spectrum disorder or Tourette's. The pattern itself can look indistinguishable from autistic stereotypies, but is much more prolonged than tics."
Tourette Syndrome, Advances in Neurology, Vol. 85. Editors, Donald J. Cohen, MD, Joseph Jankovic, MD, Christopher G. Goetz, MD. Lippincott, Williams & Wilkins, November, 2000. ISBN: 0-7817-2405-8 Chapter 7: Autism Spectrum Disorders: Relevance to Tourette Syndrome, Isabelle Rapin.
Other FAQ (Frequently Asked Questions) about Tourette's syndrome may help sort out additional factors which should be considered when pursuing a Tourette's diagnosis:
Tourette Syndrome - Now What?
TSNW - TSNowWhat - TouretteNowWhat - Tourette's Syndrome Now What?