Tics are repeated, sudden, rapid, nonrhythmic muscle movements including sounds or vocalizations. Tourette syndrome is diagnosed when people have had both motor and vocal tics for > 1 year. Diagnosis is clinical. Tics are treated only if they interfere with a child's activities or self-image; treatment may include Comprehensive Behavioral Intervention for Tics and alpha-adrenergic agonists or antipsychotics.

Tics vary widely in severity; they are common among children, many of whom are not evaluated or diagnosed. Tourette syndrome, the most severe type of tic disorder, occurs in 3 to 8/1000 children. Male to female ratio is 3:1 (1, 2).

Tics begin before 18 years of age (typically between 4 years and 6 years of age); they increase in severity to a peak at about 10 to 12 years of age and decrease during adolescence. Eventually, most tics disappear spontaneously. However, in about 1% of children, tics persist into adulthood.

Etiology is not known, but tic disorders tend to be familial. In some families, they appear in a dominant pattern with incomplete penetrance.

Comorbidities

Comorbidities are common.

Children with tics may have one or more of the following:

• Attention-deficit/hyperactivity disorder (ADHD)
• Obsessive-compulsive disorder (OCD)
• Anxiety disorders
• Learning disorders

These disorders often interfere more with children's development and well-being than the tics do. ADHD is the most common comorbidity, and sometimes tics first appear when children with ADHD are treated with a stimulant; these children probably have an underlying tendency to tics.

• Adolescents (and adults) may have
• Depression
• Bipolar disorder
• Substance use disorder

• Classification of Tic Disorder

Tic disorders are divided into 3 categories by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5):

• Provisional tic disorder: Single or multiple motor and/ or vocal tics have been present < 1 year.
• Persistent tic disorder (chronic tic disorder): Single or multiple motor or vocal tics (but not both motor and vocal) have been present for > 1 year.
• Tourette syndrome (Gilles de la Tourette syndrome): Both motor and vocal tics have been present for > 1 year.

These categories typically form a continuum in which patients begin with provisional tic disorder and sometimes go on to persistent tic disorder or Tourette syndrome. In all cases, age at onset must be < 18 years and the disturbance cannot be due to the physiologic effects of a substance (eg, cocaine) or another disorder (eg, Huntington's disease, post-viral encephalitis).

• Symptoms and signs of Tic Disorder

Patients tend to manifest the same set of tics at any given time, although tics tend to vary in type, intensity, and frequency over a period of time. They may occur multiple times in an hour, then remit or barely be present for ≥ 3 months. Typically, tics do not occur during sleep.

Tics can be

·         Motor and/or vocal

·         Simple or complex

(See table Types of Tics .)

Simple tics are a very brief movement or vocalization, typically without social meaning.

Complex tics last longer and may involve a combination of simple tics. Complex tics may appear to have social meaning (ie, be recognizable gestures or words) and thus seem intentional. However, although some patients can voluntarily suppress their tics for a short time (seconds to minutes) and some notice a premonitory urge to perform the tic, tics are not voluntary and do not represent misbehavior.

Stress and fatigue can make tics worse, but tics are often most prominent when the body is relaxed, as while watching TV. Tics may lessen when patients are engaged in tasks (eg, school or work activities). Tics rarely interfere with motor coordination. Mild tics rarely cause problems, but severe tics, particularly coprolalia (which is rare), are physically and/or socially disabling.

Sometimes tics are explosive in onset, appearing and becoming constant within a day. Sometimes children with explosive-onset tics and/or related obsessive compulsiveness have a streptococcal infection—a phenomenon sometimes called pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). Many investigators do not believe that PANDAS is distinct from the spectrum of tic disorders.

• Diagnosis of Tic Disorder

-          Clinical evaluation

-          To differentiate Tourette syndrome from transient tics, physicians may have to monitor patients over time. Tourette syndrome is diagnosed when people have had both motor and vocal tics for > 1 year.

• Treatment of Tic Disorder

-         Comprehensive Behavioral Intervention for Tics (CBIT)

-         Sometimes alpha-adrenergic agonists or antipsychotics

-         Treatment of comorbidities

·         Key points

·         Tics are repeated, sudden, rapid, nonrhythmic muscle movements or vocalizations that develop in children < 18 years old.

·         Tics are common among children, but coprolalia, a notoriously known form of vocal tic, is rare.

·         Simple tics are very brief movements and/or vocalizations (eg, head jerk, grunt), typically without social meaning.

·         Complex tics may appear to have social meaning (ie, be recognizable gestures or words) and thus seem intentional, but they are not.

·         Strongly consider Comprehensive Behavioral Intervention for Tics (CBIT) as the initial treatment option for tics.

·         An alpha-adrenergic agonist such as clonidine or guanfacine is beneficial for both mild tics and ADHD.

·         An antipsychotic may lessen severe or difficult-to-control tics but may cause more adverse effects.