Tics and Tourette Syndrome in Children and Adolescents

Movement disorders in childhood are a common presentation in pediatric settings and can include tics, stereotypies, tremor, myclonus, chorea, and parkinsonism. Most movement disorders occuring in childhood are hyperkinetic (excess movement). Here, we discuss the most common movement disorders of childhood and adolescence: tics and stereotypies. The underlying etiology of such movement disorders can vary and may be associated with various clinical syndromes.

Tics are defined as brief, repetitive, coordinated movements (motor tics) or sounds (phonic tics) of varying intensity. Motor tics can resemble gestures and fragments of normal behavior but are performed at irregular intervals. Phonic, or vocal, tics are sounds generated by a combination of respiratory, laryngeal, pharyngeal, oral, and nasal muscles.

Voluntary Nature of Tics

Most tics are considered semivoluntary because they are unwanted movements preceded by an inner sensory stimulus (a premonitory urge) that is relieved with performing the tic.¹ However, they are also sometimes briefly suppressible with some voluntary control. Children can describe premonitory sensations such as burning feeling in the eye, tension buildup in the neck or limb, nasal stuffiness, itching, or throat dryness.

Prevalence and Progression of Tics

The prevalence of tics in pediatric populations varies considerably (approximately 19% to 24%) with various studies reporting motor tics observed in 22% of preschool students, 7.8% in elementary school students, and 3.4% in adolescents.² Tics are more common in boys than in girls with a ratio of 3-4:1.³

The progression of tics varies and may occur in short-term bursts or with a long-term waxing and waning course. In addition, the frequency, distribution, and intensity of tics can fluctuate over time. As with many other movement disorders, tics can be exacerbated with stress, fatigue, excitement, anger, sleep deprivation, acute illness, and anxiety.

Tics are classified as simple or complex.⁴ Subclassifications are described below.

Simple Tics

Simple motor tics involve one group of muscles:

• blinking

• nose twitching

• head jerking

• shoulder shrugging

• oculogyric deviation (eye-rolling)

• eyebrow raising

• facial grimacing

• abdominal tensing

• specific limb movements

Simple phonic tics include:

• sniffing

• throat clearing

• grunting

• squeaking

• coughing

• screaming

• blowing air and sucking sounds

• whistling or making bird/animal noises

Complex Tics

In contrast, complex motor tics involve coordinated, sequenced movements that resemble normal gestures but are nonpurposeful, intense, and irregularly timed. Examples of complex motor tics include:⁵

• imitating gestures of other people (echopraxia)

• inappropriate gestures or touching of genitalia (copropraxia)

• complex movements that involve throwing, jumping, kicking, punching, or hitting

Similarly, complex phonic tics may include:

• shouting profanities (coprolalia)

• repeating someone else’s words (echolalia) and one’s own phrases (palilalia)

In rare instances, some patients have self-injurious tics such as neck whiplash, head banging, lip biting, skin picking, self-hitting, and wound scratching.⁶

See also, functional tics below.

Tourette Syndrome

The most common cause of organic tics in children and adolescents is Tourette syndrome, which is a neurobehavioral disorder defined as multiple motor and vocal tics for at least 1 year with an onset prior to 18 years of age.² Tourette syndrome (TS) is often associated with multiple psychiatric comorbidities such as attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), impulsivity, depression, anxiety, and disruptive behavior.

The worldwide prevalence of TS in non-disabled school children is approximated at around 0.3% to 0.8% with higher prevalance (up to 11%) noted in children with autism spectrum disorder (ASD).²˒⁷ The onset of tics is usually between 3 and 8 years of age, with initial symptoms involving motor tics of the face and head. Phonic tics usually develop a few years after the onset of motor tics. The peak severity of tics in TS is between 10 to 12 years of age.⁸ By early adulthood, most individuals with TS have significant improvement or complete resolution of tics. However, tics can persist into adulthood in approximately 50% of people, but remain largely non-bothersome and mild in severity.²˒⁹

Diagnosis of tics and TS relies on history and clinical observation of tics. If tics are not present during examination, it is important to ask the parents to record a video of the tics to better understand their characteristics and severity. Once a tic disorder has been established, it is important to identify any underlying psychiatric comorbidities and family history of tics and psychiatric comorbidities, both of which would help support the diagnosis of TS. Tic disorders, including TS, are considered to be polygenic inherited disorders (involving multipe different genes) with a reported heritability of 0.77 according to a large population based cohort study.¹⁰

Other Causes of Organic Tics

Prior to a diagnosis of TS, other causes of organic tics (see also functional tics below) should be ruled out in the pediatric population. Potential causes may include Huntington’s disease, post-viral encephalitis, substance abuse (stimulants such as cocaine and amphetamines), head trauma, stroke, carbon monoxide poisoning, and medication side effects (tardive tics with the use of antipsychotics).²˒⁷

Chronic motor tics are also commonly associated with children affected by ASD and intellectual disability.

Pharmacotherapy may be utilized to manage tics when needed or desired by the patient/parent. More on tic treatment below.

During the COVID-19 pandemic, there has been a surge of tic-like behaviors classified as functional tics in patients without a prior history of tics. These tic-like behaviors are predominantly affecting adolescent females compared to males and have resulted in a mass sociogenic illness with behaviors spreading spontaneously through a group.¹¹

Although functional tics share many common features with organic tics (such as tics in TS), there are several distinct clinical features to help distinguish functional tics from organic tics.¹²˒¹³ These distinct features include abrupt, explosive onset of tic-like movements, suggestibility on examination, and high degree of distractibility. In addition, these patients usually deny any localized premonitory urge and also lack suppressibility of tics, both features commonly observed in organic tics.

The rise in functional tics among adolescents during the pandemic has largely been contributed by exposure to popular tic-related videos on social media platforms such as TikTok and YouTube. The use of pharmacotherapy is not recommended for functional tics; reassurance and behavioral interventions to address underlying stressors are essential for improvement of symptoms.¹⁴

A stereotypy is an involuntary, repetitive, rhythmic, and patterned movement or vocalization with soothing properties that occurs in a purposeless manner.⁷ Stereotypies most commonly occur with boredom, excitement, concentration, or nervousness but are often distractible and can abate with redirection.

Examples of stereotypies include:

• leg shaking

• body rocking

• drumming fingers

• clicking a pen

• skin picking

• pacing

• complex hand movements

• humming

• moaning

For most clinicians, distinguishing between tics and stereotypy in children and adolescents can be challenging. Stereotypy usually occurs before age 3 and can be seen as early as infancy.⁷ In comparison to tics, stereotypies are commonly fixed in pattern, longer lasting, and rhythmic.¹⁵ Unlike tics, which are performed to relieve an unpleasant premonitory urge, stereotypies are performed due to their pleasant and soothing quality. Although stereotypies are common in normally developing children, they are typically noted in children affected with ASD and profound cognitive impairment. These pediatric populations can also develop self-injurious stereotypies such as hand biting, punching of the face, head banging, and continual skin picking.

Stereotypies are usually not treated unless they are self-injurious, in which case treatment may include mechanical barriers, behavioral therapy, VMAT2 inhibitors, SSRIs, or botulinum toxin injections (for excessive biting).⁷˒¹⁵

The management of tics in Tourette syndrome depends on whether the tics are bothersome or painful, impair daily tasks, or cause embarrassment to the child/adolescent. When this is not the case, patients with TS generally do not require treatment for their tics and can be monitored for progression.

Medication

Children and parents opting for treatment of tics are usually treated with oral pharmacotherapy. For tics that are relatively mild, alpha-2 agonists such as clonidine and guanfacine may be prescribed. Topiramate can also be prescribed for mild to moderate tics if there are no contraindications.

For more severe and persistent TS-related tics, dopamine receptor blocking agents such as fluphenazine can be a very effective treatment in children. Caution should be maintained when fluphenazine is used in children approaching adulthood as it can increase the risk of developing tardive dyskinesia with increasing age.⁷ VMAT2 inhibitors such as tetrabenazine (including deutetrabenazine and valbenazine, if approved by insurance) are also useful in treatment of tics in children and adolescents and can safely be continued into adulthood without the risk of tardive dyskinesia.¹⁶

Even though antipsychotics such as haloperidol, pimozide, and aripiprazole are effective FDA-approved treatments for TS, these treatments should not be considered first-line agents due to increased risk of developing tardive dyskinesia from their dopamine receptor blocking properties along with other side effects such as weight gain, QTC prolongation, and metabolic syndrome.

Behavioral Interventions

Many studies have noted the efficacy of comprehensive behavioral intervention for tics (CBIT) when compared to placebo.¹⁷ However, in clinical experience, CBIT as a standalone therapy is not very effective for severe tics and should be used an adjunct therapy to oral pharmacotherapy.⁷

For more focal and painful tics, botulinum toxin injections can be administered.⁷˒¹⁶˒¹⁷ Deep brain stimulation as a treatment for severe tics refractory to oral medications and CBIT may also be considered in select cases.¹⁶