ICD-10 code: F95.1
Persistent (chronic) motor tic disorder (MTD) is part of a cluster of diagnoses called the motor disorders. Motor disorders are a group of psychiatric conditions that include:
Motor disorders are a group of psychiatric conditions that affect the ability to produce and control bodily movements.
Motor disorders may involve developmental delays and deficits involving fine and gross motor functions. Developmental coordination disorder is characterized by deficits in the acquisition and execution of coordinated motor skills and is manifested by clumsiness and slowness or inaccuracy of performance of motor skills that cause interference with daily living. Stereotypic movement disorder includes patterns of repetitive and seemingly driven yet purposeless motor behaviors. Examples of such behaviors include movements of the head, body, and hands that are developmentally abnormal. Tic disorders involve sudden, rapid and recurrent, non-rhythmic motor movements or vocalizations. Such motoric or vocal manifestations are observably involuntary.
Several types of tic disorders can be distinguished in DSM-5. These are as follows:
Tourette's disorder is characterized by the presence of multiple motor tics and one or more vocal tics. Persistent (chronic) motor tic disorder is characterized by the presence of single or multiple motor tics and the absence of any vocal tics. Persistent (chronic) vocal tic disorder is characterized by the presence of a single or multiple vocal tics and the absence of any motor tics.
Tics can be simple (of short duration) and can include motor behaviors such as eye blinking, shoulder shrugging, or movement of the extremities, or vocal behaviors such as throat clearing, sniffing, and grunting. Complex tics are of longer duration (on the order of seconds) and may include combinations of motor or vocal behaviors. Complex tics may involve imitating another person's motor or vocal behaviors, sexual or obscene gestures (copropraxia) or utterances (coprolalia), or they may be apparently nonsensical combinations of motions and/or vocalizations.
Because many individuals experience one or more tics at some point in their lives, a tic disorder is diagnosed only when the tics persist for one year or longer.
The exact prevalence of MTD in adults is unknown. However, MTD begins by definition before age 18 and tends to spontaneously remit in many cases. Persistent tic disorders are thought to be present in less than 3% of children and adolescents; therefore, the prevalence in adults is likely significantly less than 3%.
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).
MTD can range from mild to severe. In severe cases, the tics can cause musculoskeletal pain or injury. Social impairments or bullying can also occur. Adults with tic disorders often experience other psychological disorders, including major depressive disorder, substance use disorder, or bipolar disorders.
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. The disorder has a genetic component, although having a predisposition to tic disorders does not mean that someone will necessarily develop a tic disorder.
MTD is treatable. However, most studies have been conducted in children and adolescents; less is known about the treatment of MTD in adults. Treatment guidelines for treating tic disorders in children and adolescents are available from the American Academy of Child and Adolescent Psychiatry and the European Society for the Study of Tourette Syndrome (ESSTS) Guidelines Group (Pharmacological Interventions and Behavioral Interventions).
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 the following treatments are effective for treating adults with tic disorders:
In addition, the following treatments are considered promising: