Clinical Manifestations

A child’s presentation depends on the nature of the habit and level of the child’s awareness of the behavior. Habit behaviors can be described as either automatic or focused, depending on the child’s level of awareness. It has been suggested that a focused style (e.g., having awareness and receiving gratification from performing the behavior) is associated with higher levels of co-occurring habits. This style in hair pulling has been linked with increased depression, anxiety, and impairment in functioning, particularly during stressful events and onset of puberty.

Teeth grinding, or bruxism, is common, can begin in the first 5 yr of life, and may be associated with daytime anxiety. Untreated bruxism can cause problems with dental occlusion. Helping the child find ways to reduce anxiety might relieve the problem; bedtime can be made more relaxing by reading or talking with the child and allowing the child to discuss fears. Praise and other emotional support are useful. Persistent bruxism requires referral to a dentist and can manifest as muscular or temporomandibular joint pain.

Thumb sucking is normal in infancy and toddlerhood. Like other rhythmic patterns of behavior, thumb sucking is self-soothing. Basic behavioral management, including encouraging parents to ignore thumb sucking and instead focus on providing the child with praise for substitute behaviors, is often effective treatment. Simple reinforcers, such as giving the child a sticker for each block of time that he or she does not suck the thumb, can also be considered. Although some literature suggests that the use of noxious agents (bitter salves) may be effective in controlling thumb sucking, this approach should rarely be necessary.

Trichotillomania is the repetitive pulling of hair resulting in loss and strand breakage of hair (Chapter 654). The usual age of onset of trichotillomania is around 13 yr, although preschoolers have been described with this disorder. Children with trichotillomania have an increasing sense of tension immediately before pulling or when resisting the behavior, followed by pleasure or relief when pulling out the hair. The prevalence of trichotillomania in children is not well known but is believed to be 1-2% in college students. Although trichotillomania often remits spontaneously, treatment of those whose disorder has been present for >6 mo is unlikely to remit and requires behavioral treatment. Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine have some success as adjuncts.

Diagnosis and Differential Diagnosis

The child should be screened for current and past psychiatric symptoms (particularly anxiety, obsessions, compulsions, and depression) along with any accompanying functional limitations. The child should be examined for any significant physical injury from habit behaviors.

The differential diagnosis includes the stereotypic movements associated with mental retardation and pervasive developmental disorders. Compulsions with obsessive-compulsive disorder (OCD) and tic disorders as well as involuntary movements associated with neurologic conditions must be considered. Developmentally appropriate self-stimulatory behaviors in young children and in persons with sensory deficits (e.g., blindness) are other considerations.

Epidemiology

Prevalence rates remain unclear given the various different manifestations of habits. Thumb sucking is common in infancy and in as many as 25% of children age 2 yr and 15% in children age 5 yr. Nail biting has a reported child prevalence as high as 45-60%. Bruxism has been observed in 5-30% of children and breath-holding spells in up to 4-5% of children younger than 8 yr. The prevalence of self-injurious behaviors in the context of mental retardation varies from 2-3% in the community to 25% of institutionalized adults with severe mental retardation.

Certain habit disorders are more common in children with developmental delays, particularly those with pervasive developmental disorders. Self-injurious habits, such as self-biting or head banging, can occur in up to 25% of normally developing toddlers, but they are almost invariably associated with developmental delays in children older than 5 yr. Habit disorders in developmentally disabled children are more refractory to treatment than those in typically developing children, and referral to a developmental pediatrician or child psychiatrist for behavioral and/or psychopharmacologic management is often indicated. The pediatrician must also rule out severe neglect, which is associated with repetitive rocking, spinning, or other stereotypies. Institutionalized children have the highest rates of these kinds of stereotypies.

Etiology

Although habit disorders are limited and diverse, given the wider variety of habit behaviors (hand shaking, head banging, mouthing objects, body rocking, skin picking), the literature is suggestive of repetitive abnormal grooming-like behaviors with possibly evolutionary ties to early human experience with adversity. Brain regions implicated are those involved in navigating human experience through unpredictable, anxiety-provoked emotional states (e.g., amygdala and hippocampus) as well as regions related to pleasure and reward seeking (e.g., nucleus accumbens). The latter involves the hypothesis that individuals experience some level of gratification from performing the habit behavior.

Treatment

Often the initial approach to helping children with habit behaviors is for the parents to ignore the behavior and not convey worry to their children. Generally these behaviors disappear with time and elimination of attention. If distress in the child or family, social isolation, and/or physical injury is occurring, then treatment is indicated.

Behavior therapy is the mainstay of treatment using a variety of strategies including habit reversal, relaxation training, self-monitoring, reinforcement, competing responses, negative practice, and, rarely, the use of aversive-tasting substances (for thumb sucking or nail biting). SSRIs are helpful in reducing repetitive behaviors, and they might play a role in particularly disabling and problematic behaviors, particularly those co-occurring with anxiety and obsessive-compulsive behaviors.

Clinical Manifestations

Motor tics generally involve muscles of the face, neck, shoulders, trunk, or hands. They can be divided into simple (eye blinking, neck jerking, shoulder shrugging, and cough) and complex (facial gestures and grooming behaviors). Vocal tics can also be simple (throat clearing, grunting, sniffing, barking) and complex (coprolalia [obscene words], palilalia [repetition of the patient’s words], and echolalia [repetition of words said to the patient]).

Tic disorders can be associated with obsessions, compulsions, hyperactivity, distractibility, and impulsivity as well as social discomfort, anxiety, and depression. Although most children with TD have normal intelligence, learning difficulties are common.

Tics are differentiated from dyskinesias or dystonic movements because they can be consciously inhibited for brief periods, are not present continuously, are absent during sleep, and tend to be exacerbated by emotional stress or reduced during physical or mental activity. Tics are distinguished from absence seizures because the child with tics does not have loss of awareness of surroundings and/or amnesia.

Diagnosis and Differential Diagnosis

TD and associated tic disorders must be differentiated from abnormal movements that might accompany a general medical condition (e.g., head injury, Huntington’s disease) or the direct effects of a substance (e.g., neuroleptic medication). They are different from the stereotyped movements seen in habit (or stereotypic movement) and pervasive developmental disorders. Tics must be differentiated from the compulsions seen in OCD (Chapter 23). Certain medications (e.g., stimulants) can exacerbate a pre-existing tic disorder.

Epidemiology

The onset of a tic disorder almost always occurs during childhood, developing in approximately 5-10% of early-school-aged children, with spontaneous disappearance in approximately 65% by the onset of adolescence. Multiple tics and complex vocal sounds can develop over time, peaking in severity by age 10-12 yr.

Etiology

Abnormalities in the dopamine, serotonin, and norepinephrine neurotransmitter systems have been identified in tic disorders as possible etiologic factors.

Autoimmune-mediated mechanisms continue to be investigated as having a potential etiologic role in movement disorders. Pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS) is a condition in which antibodies to group A streptococcus (Chapter 176) cross-react with basal ganglia tissue and precipitate symptoms. Data supporting the pathophysiology of PANDAS include the ability to prevent tic relapses with antibiotic prophylaxis; high rates of cross-reactive antibodies for both group A streptococcus and basal ganglia proteins found in some samples from patients with tics compared with control subjects; and enlargement of the basal ganglia during acute exacerbations of neuropsychiatric symptoms in patients with PANDAS. Five clinical characteristics define the subgroup of patients with PANDAS: the presence of OCD and/or tic disorder; prepubertal age of onset; abrupt onset and relapsing-remitting course; association with neurologic abnormalities (chorea, hyperactivity, tics) during exacerbations; and temporal association between symptom exacerbations and group A streptococcal infection (a positive antistreptolysin O titer). Treatment of PANDAS includes acute antistreptococcal antibiotic therapy; prophylactic penicillin or azithromycin can decrease the number or episodes. The role of immunotherapy is controversial, with therapeutic plasma exchange indicated only for severely affected children.

Treatment

The treatment of tic disorder generally involves a multilevel approach including education, treating co-occurring conditions, and managing disabling tics. The child and family can be helped to understand the condition including what exacerbates and what reduces the tics. Supportive counselling can prove helpful for the child and/or the family.

Cognitive-behavioral therapy can be helpful in reducing impairing co-occurring anxiety and/or compulsive symptoms. Classroom level interventions might be needed when significant academic difficulties associated with co-occurring attention-deficit/hyperactivity disorder (ADHD) and/or learning disorders are present.

Medication for tic reduction is reserved for when the tics cause marked distress or significant impairments in psychosocial functioning. The α₂-adrenergic agonists (clonidine and guanfacine) are first-line agents in treating mild to moderate tic disorders. Sedation and low blood pressure are common side effects that require careful monitoring particularly when initiating treatment. The D₂ dopamine receptor-blocking medications (haloperidol and pimozide) are effective in reducing tics, but side effects including extrapyramidal symptoms have limited their use as first-line treatment. Risperidone, an atypical antipsychotic medication, has been shown to be equivalent to clonidine in reducing tics, though it too can have extrapyramidal as well as metabolic side effects (see Table 19-5).

Children with tic disorders might benefit from an SSRI for the treatment of comorbid OCD as well as anxiety and depressive disorders. Augmentation of the SSRI with an atypical antipsychotic medication is a consideration in patients with tic disorders and OCD who respond poorly to an SSRI alone. The presence of tics does not preclude the use of stimulants to address comorbid ADHD. However, close clinical monitoring is required for possible exacerbation of tics during stimulant treatment in an effort to strike a careful balance between reducing ADHD symptoms and controlling the tics.

Clinical Manifestations

Tourette’s syndrome (TS) is characterized by multiple motor and vocal tics (not necessarily present concurrently). TS occurs in approximately 4-5 persons per 10,000. It is 1.5-3 times more likely in boys than in girls. TS commonly manifests in childhood, beginning with simple motor tics, often before age 7 yr. In many cases, multiple tics and complex vocal sounds, such as barking and grunting, develop over time and peak in severity by age 10-12 yr. Shouting obscene words (coprolalia) is characteristic but is seen in only 10% of affected patients. The vocalizations can be suppressed temporarily but ultimately are uncontrollable and often jeopardize patients’ social interaction with other children. Although TS is a lifelong condition, the ultimate prognosis can often be determined by the severity of the symptoms during adolescence. TS is more common in 1st-degree relatives of patients with TS than in the general population, and it affects boys 3-4 times more often than girls. In some, it is an autosomal dominant disorder with greater penetrance in males. Criteria for the diagnosis include multiple motor and vocal tics lasting >1 yr, with no tic-free interval lasting >3 mo, onset before age 18 yr, and no medical causes (drugs, central nervous system disease).

Children with TS often have behavioral, emotional, and academic problems. In particular, these children have higher rates of OCD (Chapter 23), ADHD (Chapter 30), and oppositional-defiant disorder (Chapter 27). The fact that TS is highly comorbid with these specific psychiatric disorders suggests dysfunction in particular regions of the brain. Neuroimaging studies suggest that there is a lack of normal asymmetry within the striatum and a decrease in the size of the cavum septum pellucidum. Single-photon emission computed tomography (SPECT) scan data implicate dysfunction in dopamine receptor binding in severely affected children. Studies have also implicated systemic and local cytokine responses in TS and in the exacerbation of symptoms.

Lyme disease rarely occurs with clinical manifestations of TS (Chapter 214). Many environmental factors are emotional stressors, which can also precipitate or increase tics. Laboratory studies are nonspecific; many patients with TS have nonspecific abnormal electroencephalographic findings.

Treatment

Treatment for TS should only occur after careful consideration of the functional limitations associated with the child’s symptoms, any associated symptoms, and the risks and benefits of pharmacotherapy. In many cases, supportive management is all that is indicated. Many children with TS require medication for obsessive-compulsive symptoms or attention and impulsivity problems. There has been a concern that stimulants will unmask tics; studies have not consistently substantiated this concern. Tic disorders are not a contraindication to the judicious use of stimulants.

Pharmacotherapy, targeting the tics themselves, is indicated when tics interfere with social development or classroom function. For 1st-line treatment, haloperidol and pimozide reduce the severity of tics by 65%. Because potentially severe side effects are associated with traditional neuroleptics (cognitive impairment, lethargy, depression, dystonic reactions, parkinsonism, tardive dyskinesia), many clinicians recommend risperidone. Risperidone is equivalent to clonidine in reducing tics. Clonidine, an α₂-agonist, is effective; sedation and low blood pressure are common side effects of clonidine and require careful monitoring. The role of guanfacine (Tenex), which is a less sedating α₂-agonist, has not been firmly established (see Table 19-5).

Affected children and their families should be encouraged to be active participants in the management of TS. Support from organizations such as the Tourette Syndrome Association, which has a user-friendly website (www.tsa-usa.org), is often very beneficial to affected families. The natural course of TS includes a significant diminution or remission in symptoms in adolescence and early adulthood in approximately 65% of cases. It is difficult to predict which patients will experience fewer symptoms over time.

Obsessive-compulsive symptoms can persist into adulthood.