Disorders usually first diagnosed in
infancy, childhood, or adolescence.
Stereotypic Movement Disorder--

Stereotypic movement disorder
is a disorder of childhood involving repetitive, nonfunctional motor behavior
(e.g., hand waving or head banging), that markedly interferes with normal activities or results in bodily injury, and
persists for four weeks or longer. The behavior must not be due to the direct effects of a substance or another
medical condition. In cases when mental retardation is present, the stereotypic or self-injurious behavior must be of
sufficient severity to become the focus of treatment. The behavior is not better explained as a compulsion (e.g.,
OCD), a tic, a stereotypy as part of a Pervasive Developmental Disorder, or hair pulling (trichotillomania).[1]

Former versions of the DSM (Diagnostic Manual and Statistical Manual of Mental Disorders) used the term
Stereotypy/Habit Disorder to designate repetitive habit behaviors that caused impairment to the child.

The repetitive movements that are common with this disorder include thumb sucking, nail biting, nose-picking,
breath holding, bruxism, head banging, rocking/rhythmic movements, self-biting, self-hitting, picking at the skin,
hand shaking, hand waving, and mouthing of objects.

Childhood habits can appear in various forms, and many people engage in some habits during their lifetime. Habits
can range from relatively benign behaviors (e.g.; nail biting) to noticeable or self- injurious behaviors, such as teeth
grinding (bruxism). Many habits of childhood are a benign, normal part of development, do not rise to the diagnostic
level of a disorder, and typically remit without treatment.

When stereotyped behaviors cause significant impairment in functioning, an evaluation for stereotypic movement
disorder is warranted. There are no specific tests for diagnosing this disorder, although some tests may be ordered
to rule out other conditions. Other conditions which feature repetitive behaviors in the differential diagnosis include
obsessive-compulsive disorder, tricho- tillomania, vocal and tic disorders (e.g.; Tourette syndrome).

Although not necessary for the diagnosis, stereotypic movement disorder most often affects children with mental
retardation and developmental disorders. It is more common in boys, and can occur at any age. The cause of this
disorder is not known.

Stereotypic movement disorder is often misdiagnosed as tics or Tourette's. Unlike the tics of Tourette's, which tend
to onset around age six or seven, repetitive movements typically start before age 2, are more bilateral than tics,
consist of intense patterns of movement for longer runs than tics. Tics are less likely to be stimulated by excitement.
Children with Stereotypic movement disorder do not always reported being bothered by the movements as a child
with tics might.

Prognosis depends on the severity of the disorder. Recognizing symptoms early can help reduce the risk of
self-injury, which can be lessened with medications. Stereotypic movement disorder due to head trauma may be
permanent. If anxiety or affective disorders are present, the behaviors may persist.[2]

References

1. ^ Stereotypic movement disorder. BehaveNet. Retrieved on 2007-08-27.
2. ^ PMID 8617696
* DSM-IV - DSM-IV criterion
* eMedicine - Excerpt from Childhood Habit Behaviors and Stereotypic Movement Disorder
* eMedicine - Childhood Habit Behaviors and Stereotypic Movement Disorder
* WebMD
* Roger Freeman, M.D., blog, former advisory board member of Tourette Syndrome Association.