Persistent (Chronic) Motor Tic Disorder in Children and Adolescents

MTD is characterized by the presence of one or more motor tics and the absence of any vocal tics during the illness. The tics are repetitive (i.e., the individual repeatedly performs the same tic[s] rather than displaying a random pattern of motor behaviors), sudden, rapid, and non-rhythmic.  Many individuals with MTD report that the tics are difficult to resist performing; however, they may be suppressed for a limited time period in certain situations. Tics may be performed in response to a sensation, bodily discomfort, or an urge (called a premonitory urge).

Tic disorders are characterized by abnormalities of brain function that are thought to underlie symptoms.  In particular, there is evidence that abnormal activation in the cortico-striato-thalamo-cortical pathways, which are implicated in motor behavior, may underlie symptoms.  Dopaminergic dysfunction has also been proposed to play a role in tic disorders.  In addition, the sense of relief that an individual experiences after performing a tic is thought to maintain symptoms.  There is also some evidence that tic disorders can begin following streptococcal infections (called pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, or PANDAS); however, the neurobiology of these cases is not well understood.  The disorder has a genetic component, although having a predisposition to tic disorders does not mean that someone will necessarily develop a tic disorder.

Note that clinical practice guidelines group the tic disorders together and do not make separate recommendations for MTD per se.  This reflects a tendency for clinical research to group tic disorders together.  The treatments described below follow the clinical practice guidelines; however, note that the treatments listed below may not have been studied in MTD per se.

Clinical research suggests that the following treatments are indicated for the treatment of children with tic disorders:

• Behavioral therapy has the strongest empirical support as a non-pharmacological intervention for tic disorders.  Behavioral therapy often includes elements of habit reversal training, which involves increasing awareness, developing a competing response, and eliciting social support.  Comprehensive Behavioral Intervention for Tics (C-BIT) is one form of habit reversal therapy-based intervention with good empirical support.
• Pharmacotherapy can also be considered in the case of moderate to severe tics.  However, Cochrane reviews and the European Society for the Study of Tourette Syndrome note that the relatively small number of controlled trials to date precludes firm recommendations about medications of choice.  Therefore, treatment decisions should carefully weigh the benefits against the expected risks and side effect profiles.  The following medications have shown positive effects in children and adolescents with tic disorders in randomized controlled trials:
• Haloperidol
• Pimozide
• Clonidine
• Deprenyl
• Peroglide
• Ziprasidone
• Risperidone
• Guanficine
• Despiramine
• Atomoxetine
• Metoclopramide
• Topiramate

In addition, the following treatments are considered promising:

• Benzamides, which are D2 dopamine receptor antagonists, specifically tiapride and sulpiride
• The atypical antipsychotics olanzapine (in adolescents), quetiapine, and ziprasidone
• Clonazepam (in adolescents), a benzodiazepine
• Baclofen, which is a GABA B receptor

In children where PANDAS is strongly suspected, there is some preliminary evidence that plasma exchange and intravenous immunoglobin may be effective for reducing symptoms.  There is also some support for prophylaxis with penicillin or azithromycin in a small prospective study of children fulfilling PANDAS criteria.