Childhood Habit Behaviors and Stereotypic Movement Disorder 

Updated: Dec 04, 2015
Author: Cynthia R Ellis, MD; Chief Editor: Caroly Pataki, MD 

Overview

Practice Essentials

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), designates repetitive habit behaviors that cause impairment as stereotypic movement disorder.[1] Complex motor stereotypies and head nodding fulfill DSM-5 criteria for stereotypic movement disorder.

Signs and symptoms

The history consists of reports of observed specific behaviors associated with the individual habit. Common stereotypies include the following:

  • Thumb or hand sucking

  • Body rocking

  • Head banging

  • Nail biting (most common stereotypy of later childhood)

  • Trichotillomania

  • Bruxism

Complex motor stereotypies include the following:

  • Flapping

  • Waving

  • Opening and closing of a fist

  • Finger wiggling

  • Wrist flexion and extension

  • Atypical gazing at objects or fingers (secondary stereotypies described in children with autism)

  • Abnormal pacing, running, and skipping (secondary stereotypies strongly associated with autism)

The characteristics of head nodding are slightly different from those of complex motor stereotypies of the limbs.

A birth and developmental history, a comprehensive family history, and a drug history should also be taken.

Physical examination is guided by the history and the types of stereotypies present. Most childhood habits are benign and have no specific observable physical signs, aside from the movements themselves. Signs, when present, may include the following:

  • Thumb and digit sucking - If continued beyond age 4-5 years, dental problems, increased risk of accidental ingestions and pica, thumb callus and skin breakdown, deformities of the fingers and thumbs, and paronychia

  • Nail biting - Extremely short fingernails, paronychia, oral herpes, herpetic whitlow, damaged dentition, apical root resorption, fractures to the incisors, and gingivitis

  • Nose picking - Epistaxis, perforation of the nasal septum, infection

  • Bruxism - Chronic dental pain, dental fractures, wearing down of dental enamel, thermal hypersensitivity of the teeth, hypermobility of the teeth, injury to the periodontium, pulpitis, dysfunction of the temporomandibular joint, recurrent headaches

  • Breath-holding spells - Injury (from a fall), seizure

  • Head banging - Callus formation, abrasions, contusions; skull fractures, eye injuries, and dental injuries are rare

See Presentation for more detail.

Diagnosis

Problems to be considered include the following:

  • Autism spectrum disorders

  • Childhood disintegrative disorder

  • Obsessive-compulsive disorder

  • Pervasive developmental disorder

  • Schizophrenia

  • Status epilepticus

  • Trichotillomania

  • Abuse

  • Bobbing head doll syndrome

  • Central nervous system (CNS) disease

  • Congenital blindness or deafness

  • Developmentally appropriate self-stimulatory behaviors in young children

  • Environmentally based sensory deprivation

  • Factitious disorder with predominately physical signs and symptoms

  • Mannerisms

  • Myoclonus

  • Neglect

  • Neurologically based movement disorder (eg, chorea, dystonic movements, athetosis, myoclonus, hemiballismus, or spasms)

  • Pain

  • Poisoning (eg, with amphetamine or cocaine)

  • Seizure disorder

  • Self-mutilation associated with certain psychotic disorders and personality disorders

  • Self-stimulatory behaviors in individuals with hearing impairment or other sensory deficits

Consultation with a developmental-behavioral pediatrician, a child psychologist, or a child psychiatrist may be indicated.

See DDx and Workup for more detail.

Management

Childhood habits that do not interfere with everyday functioning often require no treatment. However, those that cause substantial distress, social isolation, or physical injury may warrant a therapeutic intervention. Treatments may include the following:

  • Physical measures (eg, helmets, dental occlusion splints)

  • Behavioral therapy (mainstay of treatment)

  • Pharmacotherapy

Effective behavioral therapies for habits include the following:

  • Habit reversal with differential reinforcement

  • Relaxation training

  • Self-monitoring

  • Reinforcement

  • Nocturnal biofeedback (for bruxism)

  • Competing responses

  • Use of bitter-tasting substances (for nail biting)

  • Negative practice

  • Use of aversive-tasting substances (for thumb sucking)

Most common habits in children that require treatment can be substantially improved by means of behavioral interventions, without the use of medication. Pharmacologic agents that may be considered as necessary include the following:

  • Naltrexone

  • Clomipramine

  • Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, sertraline, and fluvoxamine

Isolated successes have also been reported with traditional and newer neuroleptics; however, because of their adverse effects, their use in this setting is discouraged.

See Treatment and Medication for more detail.

Background

Childhood habit behaviors appear in numerous different forms. Many people engage in some degree of habitlike behavior in their lifetime. For example, habits can range from seemingly benign behaviors, such as nail biting or foot tapping, to more noticeable physically damaging behaviors, such as teeth grinding (bruxism) and hair pulling.

Habit disorders, now subsumed under the diagnostic term stereotypic movement disorder, consist of repetitive, seemingly driven, and nonfunctional motor behaviors that interfere with normal activities or that result in bodily injury. Fortunately, many childhood habits are benign, are considered a normal part of development, and do not meet the criteria for a disorder; such habits typically remit without treatment.

Stereotypies are repetitive, purposeless actions that are most commonly seen in childhood. They do not have a clear definition, because of the wide range of possible stereotyped behaviors and the overlap with other movement or behavioral disorders.[2] Nevertheless, it is helpful to classify stereotypies into general categories so as to distinguish between the different movements. The following 3 categories are proposed[3] :

  • Common stereotypies - These are by far the most frequent type and comprise habits such as nail biting and bruxism

  • Complex motor stereotypies - These consist of various repetitive limb movements

  • Head nodding - This is a separate stereotypy that shares some characteristics with complex motor stereotypies

Complex motor stereotypies are further subdivided as follows:

  • Primary stereotypies - These occur in otherwise developmentally normal children and usually remain stable or regress

  • Secondary stereotypies - These occur in conjunction with a neurologic or behavior disorder, such as autism, intellectual disability, Tourette syndrome, and some rare neurodevelopmental syndromes; in older children they may be associated with schizophrenia, obsessive-compulsive disorder, or early-onset neurodegenerative diseases.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), designates repetitive habit behaviors that cause impairment to the child as stereotypic movement disorder.[1] Complex motor stereotypies and head nodding fulfill the DSM-5 criteria for stereotypic movement disorder.

Other involuntary movements that may present similarly to stereotypies include tics and automatisms. A tic disorder is by far the most common misdiagnosis in patients with stereotypic movement disorder. Complex motor tics are also repetitive, involuntary actions; however, they usually have a later age of onset, are more variable in movements and rhythms, and are briefer. More important, stereotypies, unlike tics, are not associated with premonitory urges and subsequent relief from those urges.

Voluntary repetitive movements that mimic stereotypies include attention deficit hyperactivity disorder (ADHD), mannerisms, and compulsions. ADHD tends to be characterized by more generalized and restless actions than stereotypies are. Mannerisms are rarely continual and accompany a normal activity. Compulsions comprise repeated ritualistic movements to relieve anxiety or fear and may occur with tics and stereotypies.

This article also addresses various common childhood behaviors (eg, thumb sucking, nail biting, nose picking, breath holding, bruxism, head banging, and rocking or rhythmic movements). Mild forms of some of these behaviors do not interfere with normal daily activities and thus are not psychiatric disorders; however, they can progress to cause functional impairment or physical or psychological sequelae or stigmatization. When functional impairment is substantial, the diagnosis of stereotypic movement disorder should be considered.

Some childhood habits remain unnoticed and can persist if left untreated, even when they interfere with optimal functioning. Childhood habits can result in negative social interactions and avoidance by peers and family members. Some repetitive behaviors can cause damage. For example, bruxism (teeth grinding) can result in tooth damage. Occasional hair pulling can result in hair loss or evolve into a more severe disorder, trichotillomania.

In most children who are otherwise developing normally, however, few of these habits result in permanent physical damage. In some cases, treating a childhood habit before clear-cut dysfunction arises may prevent serious psychopathology and social dysfunction. Much of what is known about childhood habits derives from the literature about common habit behaviors in adults.

Diagnostic criteria (DSM-5)

The specific DSM-5 criteria for stereotypic movement disorder are as follows[1] :

  • Repetitive, seemingly driven, and apparently purposeless motor behavior (eg, hand shaking or waving, body rocking, head banging, self-biting, or hitting one’s own body)

  • The repetitive motor behavior interferes with social, academic, or other activities and may result in self-injury

  • Onset is in the early developmental period

  • The repetitive motor behavior is not attributable to the physiologic effects of a substance or neurologic condition and cannot be better explained by another neurodevelopmental or mental disorder (eg, trichotillomania or obsessive-compulsive disorder)

The following specifiers are used:

  • With self-injurious behavior (or behavior that would be self-injurious if not prevented)

  • Without self-injurious behavior

Whether the stereotypy is associated with a known medical or genetic condition, developmental disorder, or environmental factor is also specified, and an additional code is used to identify the associated element.

Severity is specified as follows:

  • Mild - Symptoms are easily suppressed by sensory stimulus or distraction

  • Moderate - Symptoms necessitate explicit protective measures and behavioral modification

  • Severe - Continuous monitoring and protective measures are required to prevent serious injury

Pathophysiology

Common stereotypies

For common stereotypies, the mechanisms have not been fully clarified but appear to vary greatly with respect to the topography and frequency of the particular habit behavior.

Thumb sucking is an oral habit that involves mouthing of the thumb. Other fingers or the hand may also be involved. Nail biting consists of biting on or chewing the nails of the hand.

Nose picking is the insertion of a finger into a nostril and may involve the removal of nasal discharge (ie, snot or “boogers”). Older children and adults are most likely to pick their nose in private, whereas young children may commonly do this in public view.

Bruxism is the forcible gnashing, grinding, clicking, or clenching of teeth. Nocturnal bruxism occurs during sleep, and the child is usually unaware of the problem. Episodes are typically brief, lasting 8-9 seconds, with audible grinding noises. Diurnal (daytime) bruxism is primarily associated with clenching of the teeth and generally does not produce audible noises. Diurnal bruxism is related to other oral habits, such as nail biting or lip chewing.

A breath-holding spell is a paroxysmal event in which a child stops breathing at end-expiration after crying, typically because of pain or anger. The crying may be brief or prolonged. Breath-holding spells may be divided into the following 3 categories:

  • Simple breath-holding spells - These result when the child becomes apneic (cyanotic or pale) but then takes a deep breath; spells with loss of consciousness and muscle tone are classified by the child’s color during the event

  • Cyanotic breath-holding spells - In these spells, which typically have an emotional precipitant (eg, anger or frustration) and typically last less than 1 minute, the child progresses from cyanotic to apneic and may then become limp and lose consciousness; if a seizure occurs, the results from electroencephalography (EEG) performed during rest or sleep are normal

  • Pallid breath-holding spells - In these spells, which are generally observed in response to pain, the child quickly becomes apneic and pale; an enhanced vagal response has been postulated to be a precursor to bradycardia or asystole; seizures rarely result

Head banging is the rhythmic hitting of the head (usually the frontal or parietal region) against a solid surface. In children who are developmentally normal, this behavior usually lasts less than 15 minutes, but it can last hours in some cases. A high frequency of up to 60-80 hits per minute is common. Head banging can be associated with temper tantrums, tension, or stress. It can also develop as a sleep ritual if it occurs as the child falls asleep.

Body rocking usually involves a forward and backward rhythmic swaying of the trunk at the hips, generally from a sitting or quadruped position. The intensity may be gentle, or it may be forceful enough to move the child’s crib or bed. This behavior typically occurs when children are alone in their cribs or beds. Most episodes last less than 15 minutes but may persist up to 30 minutes. Rhythmic or stereotypic behaviors include repetitive nonfunctional motor movements, such as hand flapping or shaking, self-biting, or hitting one’s own body.

Complex stereotypies

Research on the mechanisms of complex motor stereotypies has followed 2 different approaches. Psychogenic hypotheses aim to explain the cause of stereotypies from a behavioral standpoint. Neurobiologic hypotheses look at the structural and molecular basis for stereotypies.

Psychogenic hypotheses

Stereotyped behaviors are known to occur in animals, especially those that are caged or restrained. One hypothesis is that such animals experience a lack of external stimuli, and the stereotypic movements help maintain their state of arousal. In support of this view, stereotypies are more common in children with sensory deprivation due to blindness or deafness and in conditions where there is less interaction with the external environment (eg, autism).[4]

Another hypothesis is that stereotyped movements are a method of expending excess energy or attention. Attending to the movements may help to diminish other unwanted or unpleasant stimuli, as a form of negative reinforcement. From a related perspective, sensory stimulation in various stereotypies is proposed as automatic positive reinforcement that causes the actions to persist.

For example, vestibular stimulation may reinforce head banging. It is more common in infants with otitis media who have an unwanted stimulus (eg, ear pain). Sensory extinction has been shown to reduce the behaviors.[5] In the case of a child whose stereotypy consisted of spinning plates on a hard surface, placement of a carpet removed the sound of the spinning plate, leading to a decrease in the frequency of the behavior.

Neurobiologic hypotheses

Anatomically, the basal ganglia are implicated in stereotypic disorders.[6] In monkeys, stereotypies are correlated with neuronal activity in the striatum, especially the putamen. Intrastriatal injection of amphetamine, which increases dopamine levels, causes stereotypies in rodents.[7]

In humans, case reports of stereotyped movements have spontaneously emerged after lesions of the putamen, orbitofrontal cortex, or thalamus. A volumetric magnetic resonance imaging (MRI) study in children with complex motor stereotypies demonstrated a reduction in the size of the caudate nuclei and also in frontal white matter.[8] Precise localization within the basal ganglia and corticostriatal circuitry is yet to be achieved.

Dopaminergic pathways appear to mediate complex motor stereotypies.[9] In the treatment of Parkinson disease, patients receiving high doses of levodopa sometimes perform repetitive, purposeless actions, known as punding. In addition, levels of plasma homovanillic acid, a dopamine metabolite, are reduced in adults with stereotypies.[10]

Studies in rodents have shown that administration of dopamine can produce repetitive behaviors such as sniffing or head bobbing.[2] From studies investigating the effect of selective dopamine agonists, dopamine D2 receptors are known to be important in enhancing stereotypies.[7]

Etiology

Although the origins of most habit disorders are not well established or understood, associated biologic or environmental etiologic factors may exist. Some habit behaviors emerge from normal repetitive behaviors in infancy (eg, hand and thumb sucking) and are believed to represent intrinsic movement patterns generated by the developing nervous system. Certain behaviors (eg, nose picking, which may initially arise as a response to dry nasal membranes and nasal irritation or itching) can later develop into a cycle that is difficult to break.

Some behaviors may start spontaneously and then may be inadvertently reinforced or maintained by other factors, such as attention. Behaviors that produce arousal or modulate self-stimulation may also be influenced by the level of environmental stimulation; for example, some behaviors may be viewed as entertainment for a bored child or as a means of coping with overstimulation.

Repetitive or habitual behaviors may be associated with an underlying condition, such as a sensory impairment or developmental disorder, an unrecognized medical or neurologic condition, the side effect of a medication, or a psychiatric disorder. Certain genetic syndromes are associated with repetitive behaviors (eg, skin picking in Prader-Willi syndrome, hand flapping in fragile X syndrome).

Thumb sucking is initially a biologically driven reflexive behavior that is often documented in utero and in the young infant. In older infants and toddlers, it is reinforced as a form of self-stimulation or self-comfort and is most often seen when the child is sleepy, hungry, frustrated, or fatigued. Most children who suck their thumbs past infancy develop the habit before the age of 3-9 months. Children who have stopped thumb sucking may resume the behavior after an acute or chronic distressing event (eg, illness, hospitalization, or separation).

Nose picking occurs in children and adults. Older children and adults are most likely to pick their nose in private, whereas young children commonly do so in public view. The behavior may begin in association with rhinorrhea, nasal irritation, or nasal itching resulting from colds or allergies.

Breath-holding spells are generally observed in response to anger or pain. In pallid breath-holding spells, an enhanced vagal response has been postulated to be a precursor to bradycardia or asystole.

Head banging can be associated with temper tantrums, tension, or stress. In some children, it can also develop as a sleep ritual. Neurologic or psychological precursors are rarely identified. Head banging is most commonly associated with developmental delay or autism. In some cases, the onset of head banging has been associated with teething or otitis media and has been hypothesized to serve a pain-relieving function.

Genetic factors

Some complex motor stereotypies appear to exhibit mendelian inheritance in animal and human studies. In a study of developmentally normal children, 25% had a family history of stereotypies, and a first-degree relative was affected in 17% of cases.[11] Nearly half of the children had a coexisting behavioral disorder.

To date, no specific genes have been identified. A causative role for the MECP2 gene on the X chromosome has been suggested. Those patients who have a detectable mutation in the gene show a greater number of stereotypies than those without a known mutation.[12]

Epidemiology

United States and international statistics

Accurate prevalence figures for childhood habits are extremely difficult to estimate, because of the various classes of habits and the differing topographies of a child’s presenting habit. Data on the prevalence of stereotypies are limited, especially internationally, and tend to vary according to the exact definition used by the researchers. Nevertheless, habits or common stereotypies are thought to occur in as many as two thirds of infants and in 20-50% of children overall.[13]

Thumb and hand sucking are seen in 17-59% of children younger than 15 years. Thumb sucking is common in infancy and in as many as 25-50% of 2-year-old children; however, it is observed in only 15-20% of 5- to 6-year-old children.

Nail biting is mainly observed from preschool age to adolescence and is the most common stereotypy in school-age children and college students. The prevalence is as high as 45%-60%; in one study, it was found to exceed 60% in a group of 8-year-olds.

Few studies of nose picking have been performed. However, in one survey, as many as 91% of adults reported nose picking.

Breath-holding spells are common in as many as 4-5% of children younger than 8 years.

Bruxism is observed in 5-30% of children. The worldwide prevalence is 8%.[14]

Head banging can occur in approximately 10% of developmentally normal infants and in 3-19% of developmentally normal children younger than 3 years. It is more frequently observed in children with autism or developmental delay and in those living in institutional environments.

Body rocking and rhythmic movements occur in most infants aged 6-12 months and may be seen in 6-19% of children younger than 3 years.[15] The behavior is most often observed in children with developmental disabilities or sensory impairments; however, it persists beyond age 2 years in 3% of children with normal development.

In a psychiatric journal, the rate was determined to be only 0.6% in college students when the patients were restricted into the group having related mental tension and relief.[16] Without such restrictions, the rate of hair pulling resulting in visible hair loss is 1.5% for males and 3.4% for females.[16]

The prevalence of primary complex motor stereotypies is unknown but may be as high as 3-4% of preschool children in the United States.[17] Secondary stereotypies are of course determined by the associated disorder. Autism occurs in 1 in 20,000 live births. Stereotypies are seen in more than 60% of autistic preschool children but in only 25% of nonautistic children with similar mental ability.[18]

Stereotypies are observed in 40-60% of individuals who are institutionalized and have profound intellectual disability, 8-10% of individuals who live in the community and have moderate intellectual disability, and up to 20% of individuals who live in the community and have intellectual disability and autism.

Self-injury is less common; it is observed in 10-20% of individuals who are institutionalized and have intellectual disability, 1-3% of individuals who live in the community and have moderate intellectual disability, and up to 5% of individuals who live in the community and have intellectual disability and autism.

Age-related demographics

The age at which specific habits originate, peak, and remit is related to the individual habit behavior. The age of onset and resolution of habit behaviors may be delayed in children with developmental disabilities.

Thumb sucking may be observed in utero as early as 29 weeks’ gestation. It is common in infancy and is observed in as many as 25-50% of children aged 2 years. Rates of thumb sucking declines with increasing age; most children spontaneously stop at about age 4 years. It is observed in only 15-20% of children aged 5-6 years.

Nail biting rarely begins in children younger than 4 years. Its peak prevalence is between the ages of 8 and 11 years, but it persists in 28% of 18-year-olds. Rates as high as 45-60% are observed from preschool to adolescence.

Nose picking is common in adults and children.

Bruxism is observed in 5-20% of children. The frequency increases during childhood, peaking at age 7-10 years and decreasing after that. It is common in children and adults.

Trichotillomania begins in later childhood.

Breath-holding spells are reported to occur in 4-5% of the pediatric population. They may begin as early as infancy, and their peak incidence is at age 2-3 years. Approximately 80-90% of preschoolers with breath-holding spells stop by age 6 years.

Head banging can occur in 3-19% of developmentally normal children younger than 3 years. It usually begins at around 9 months of age and may last up to 3 years. The incidence peaks between the ages of 18 months and 2 years, declining rapidly after that. Head banging continues in 1-3% of children older than 3 years. The behavior can recur at age 5-6 years. Head banging is more frequently observed in children with autism or developmental delay or in those living in an institutional environment.

Body rocking and rhythmic movements develop in the first year of life, usually as transient phenomena during gross motor development. They occur in most infants aged 6-12 months. The prevalence peaks in children aged 6-18 months and rapidly declines after that. The behavior persists beyond age 2 years in 3% of children with normal development. Body rocking and rhythmic movements are most often observed in children with developmental disabilities or sensory impairments and may be associated with a lack of environmental stimulation.

More than 80% of complex motor stereotypies begin before age 2 years, with a peak incidence at age 6 months.[19, 11] Another 10% begin in the following year. The outcome is variable, and approximately one third of patients show resolution or improvement of stereotypies. For the most part, this happens in the first year, but it may take 10 years or longer. Stereotypies stabilize in about 60% of patients and worsen in a minority.

Sex- and race-related demographics

Just as the overall prevalence rates of childhood habits are unknown, data on sex-based differences in prevalence are limited at best. In cases of self-injurious behavior, head banging is believed to occur 3 times more frequently in male individuals than in female individuals. Self-biting may be more prevalent in female individuals than in male individuals.

Thumb sucking is suspected to occur slightly more often in girls than in boys. Nail biting also tends to be more common in females than in males. However, sex-based differences in nose picking are unknown. Breath-holding spells occur with equal frequency in boys and girls. No sex-based differences in rocking and rhythmic movements have been reported.

When the types of bruxism are separated into clenching and grinding, more females than males grind their teeth, but the number of males and females who engage in teeth clenching are equal. In addition, resulting dysfunction of the temporomandibular joint (TMJ) may be more common among female adolescents than among male adolescents.

Overall, complex motor stereotypies are nearly twice as likely to occur in males as in females. The increased prevalence of conditions such as autism or intellectual disability in males is a confounding factor, but even in primary stereotypies, males are more likely to be affected.

There are no known racial differences in the frequency of stereotypies.

Prognosis

Common stereotypies have an excellent prognosis in most cases. As a general rule, common stereotypies in infancy usually regress in later childhood. Many common stereotypies that are present in later childhood will persist into adulthood. However, the frequency and severity of the stereotypies are stable or improve with time in most children.

Because childhood habits take various forms, mortality and morbidity profiles vary widely. Mortality is extremely rare. All habits have the potential to produce social stigmatization and distress, depending on the environmental context in which they occur.

Some habit disorders, though not directly causing observable physical damage, result in impaired social functioning. Stigmatization resulting from the habit can cause the child considerable distress, humiliation, social rejection, academic problems, feelings of shame and guilt, discomfort in social activities, and depression or anxiety.

Although the range of physical sequelae varies greatly, serious medical complications are rare. A child with breath-holding spells does not have an increased risk of seizures but does have an increased risk of syncopal episodes as an adult. Data about habit behaviors as markers for increased emotional stress, anxiety, or behavior problems are inconsistent.

Self-injurious stereotypies are unusual in developmentally normal children, though they occur in as many as 40% of children with autism.[20] Such stereotypies include hand biting, severe trichotillomania, and self-hitting.

Most childhood habits that do not involve self-injury are benign and remit without intervention. When a habit persists and interferes with daily functioning, intervention is warranted. The prognosis for reducing and eliminating habit disorders is typically good. Treatment research shows that behavioral intervention can reduce the habit behavior by 90%.

Complex motor stereotypies are now known to persist in many more children than was previously thought.[21] Such stereotypies cease completely in 4% of children within 1 year of onset. In two thirds, the stereotypies last for more than 5 years from onset.[11] Head nodding has a better prognosis than other complex motor stereotypies. Half of children show regression of the behavior within 1 year of onset.[11]

Patient Education

Education of both parents and patients is an important part of management. Many Internet resources are available for common stereotypies, including the following:

  • WebMD.com, Thumb sucking

  • Babycenter.com, Head banging

  • WebMD.com, Nail biting

  • WebMD.com, Trichotillomania

  • WebMD.com, Bruxism

 

Presentation

History

The history consists of reports of observed specific behaviors associated with the individual habit. Intensity, severity, and duration may be variable. Habit behaviors may be present for a long time before consultation is sought. Complaints at the time of presentation for evaluation or treatment may be either physical or psychological sequelae of the habit (see Pathophysiology).

Common stereotypies

The range of habits or common stereotypies is described below in chronologic order. These rarely require medical attention. In some children, a natural progression is seen, beginning with thumb or hand sucking and then progressing to body rocking and head banging and, later still, to nail biting and foot or finger tapping.

Thumb or hand sucking is first seen in utero, and is the earliest common stereotypy.[22] Hand sucking rarely persists beyond infancy. Thumb sucking is not usually associated with medical sequelae unless it persists beyond the age of 4 years. It can then lead to dental malocclusion, digital deformities, temporomandibular disorders, and social stigmatization.

Body rocking is usually seen just before sleeping or after waking. Head banging often occurs during teething, ear infections, and temper tantrums. It may cause abrasions and callus formation, but only rarely does it lead to fractures or more serious injury.

Nail biting is the most common stereotypy of later childhood. It leads to shortened, irregular fingernails that may be aesthetically unpleasant. It also predisposes to paronychia and herpetic whitlow. Again, the behavior is increased with anxiety and stress.

Trichotillomania is the repeated plucking of scalp or body hair, leading to clinically significant hair loss. Most sufferers have no other comorbidities, but the condition is related to body dysmorphic disorders, personality disorders, and eating disorders.[16] The most common sites, in order of decreasing frequency, are the scalp, eyelashes, eyebrows, and pubic hair.

Bruxism can happen subconsciously at night as well as during the day. Complications include mechanical wear, teeth fractures, temporomandibular disorder pain, headache, and neck pain.[14]

Complex motor stereotypies

Complex motor stereotypies may include flapping, waving, opening and closing of a fist, finger wiggling, or wrist flexion and extension. They can be primary or secondary, and the main concern for parents and professionals is that they may be manifestations of an underlying disorder.

No clinical features enable differentiation of stereotypies seen in normally developing children from those seen in children with autism or developmental delay. In both groups, the movements can last for more than 1 minute and can occur multiple times in a day. In autism, they tend to occur for a longer duration overall.[23] The movements can be associated with other clinical features, such as skin picking, mouth opening, facial grimacing, and involuntary noises.

The most common trigger is excitement or being happy. Concentration on a task, tiredness, and anxiety are also triggers. More than 1 trigger is present in most children. In most cases, movements cease if the child is distracted (eg, by calling his or her name). Movements also do not occur in sleep.

Atypical gazing at objects or fingers has been described in children with autism.[18] These have been termed complex visual stereotypies and appear to occur only as secondary stereotypies. Abnormal pacing, running, and skipping have also been considered secondary stereotypies. Again, these are strongly associated with autism rather than other disorders.[18]

The presence of other stereotypies, tics, or obsessive tendencies should also be sought in the history because in more than one third of children, they are associated with complex motor stereotypies.

Head nodding

The characteristics of head nodding are slightly different from those of complex motor stereotypies of the limbs. Head nodding is a regular rhythmic movement of the head and neck, which may be up-and-down, side-to-side, or shoulder-to-shoulder. It has an earlier age of onset than complex stereotypies of the limbs, and episodes occur more than once daily. Head nodding is unlikely to be associated with a family history, unlike other forms of stereotypic movement disorder. In addition, most cases regress in later childhood.

Other components of history

A birth and developmental history should always be taken, including pregnancy, gestation, delivery, and developmental milestones. These may identify underlying disorders and so are essential for differentiating primary and secondary complex motor stereotypies. In autism, children show limited social and communication skills and a restricted range of activities. Even children with primary stereotypies may have mild language delay despite normal intelligence.[21]

A comprehensive family history is important because 25% of children have at least 1 affected family member.[19] The family history should also include inquiries into the presence of other developmental and movement disorders.

A drug history is also advisable. Although drugs are rarely implicated, clinicians should be aware that chronic neuroleptic drug use can lead to stereotypies, usually as part of a tardive dyskinesia. Amphetamine poisoning in children has been reported to cause self-injurious stereotypies, including head banging and hand biting.

Physical Examination

Physical examination is guided by the history and the types of stereotypies present. Most childhood habits are benign and have no specific observable physical signs, aside from the movements themselves. However, when physical signs are present, they typically are nonpathologic and often were previously unnoticed. In severe cases, physical evidence of a habit may be related to an associated injury or physical sequelae of the specific behavior the child engages in.

Thumb and digit sucking continued beyond age 4-5 years can result in dental problems, especially malocclusion, mucosal trauma, decreased alveolar bone growth, and abnormal growth of facial bones. These children also have an increased risk of accidental ingestions and pica. Thumb callus and skin breakdown may occur. Deformities of the fingers and thumbs and paronychia occur relatively infrequently.

Nail biting can be associated with extremely short fingernails, paronychia, oral herpes, herpetic whitlow, damaged dentition, apical root resorption, fractures to the incisors, and gingivitis.

Epistaxis is the most common complication of nose picking. In rare cases, complications may include perforation of the nasal septum or infection.

Bruxism can result in chronic dental pain, dental fractures, wearing down of dental enamel, thermal hypersensitivity of the teeth, hypermobility of the teeth, injury to the periodontium, and pulpitis. Dysfunction of the temporomandibular joint and recurrent headaches may also occur.

In children who have breath-holding spells, Injury may result from a fall secondary to loss of consciousness and muscle tone. In some cases, a child may have a seizure secondary to the breath holding.

Head banging rarely causes physical or intracranial injuries, even when it is forceful. Head banging may cause callus formation, abrasions, and contusions at the site of the banging. The risk of injury is increased in children with bleeding disorders. Skull fractures, eye injuries, and dental injuries have rarely been reported.

Body rocking and rhythmic movements generally do not give rise to significant physical signs. In rare cases, self-injurious rhythmic movements may occur and result in various associated physical injuries.

Efforts should also be made to look for other movement disorders, such as tics or chorea. Sensory and motor examinations identify underlying pathology. Blindness, deafness, hemiparesis, and cerebral palsy are causes of secondary stereotypies.

 

DDx

Diagnostic Considerations

Although habit disorders can affect any child, stereotypic movements and stereotypies are most common among children with intellectual disability and other developmental delays. For example, one should be cognizant of a child who has intellectual disability or developmental delay and who engages in head banging and other repetitive behaviors.

Some habitlike behavior is normal for a developing child. For example, approximately one half of all 2-year-old children engage in thumb sucking. However, if this behavior persists through childhood, the likelihood that it will become a substantial problem may increase with age. Careful observation of normal developmental behaviors should be considered before a child is evaluated for a severe problem.

The differential diagnosis of stereotypic movement disorder requires the clinician to rule out a number of other psychiatric conditions in which repetitive behaviors are core features; examples include obsessive-compulsive disorder, trichotillomania, vocal and motor tics, and Tourette disorder. When the signs and symptoms are best accounted for by one of these other disorders, stereotypic movement disorder is not diagnosed. When rarer forms of repetitive actions are present, epileptic automatisms should be kept in mind.

In addition to the conditions listed in the differential diagnosis, other problems to be considered include the following:

  • Abuse

  • Bobbing head doll syndrome

  • Central nervous system (CNS) disease

  • Congenital blindness or deafness

  • Developmentally appropriate self-stimulatory behaviors in young children

  • Environmentally based sensory deprivation

  • Factitious disorder with predominately physical signs and symptoms

  • Mannerisms

  • Myoclonus

  • Neglect

  • Neurologically based movement disorder (eg, chorea, dystonic movements, athetosis, myoclonus, hemiballismus, or spasms)

  • Pain

  • Poisoning (eg, with amphetamine or cocaine)

  • Seizure disorder

  • Self-mutilation associated with certain psychotic disorders and personality disorders

  • Self-stimulatory behaviors in individuals with hearing impairment or other sensory deficits

Differential Diagnoses

 

Workup

Approach Considerations

Although no specific activity limitations are needed in the treatment of a child with a habit disorder, some situations and contexts may perpetuate habitlike behaviors. Therefore, a functional behavioral assessment by a psychologist can help determine the types of activities that may occur in conjunction with habitlike behaviors or exacerbate such behaviors.

Consultation with a developmental-behavioral pediatrician, a child psychologist, or a child psychiatrist may be indicated.

 

Treatment

Approach Considerations

Childhood habits that do not interfere with everyday functioning often do not require any treatment, because many of them will remit spontaneously over time. However, if the habit is causing the child or family members substantial distress, social isolation, or physical injury, a therapeutic intervention may be required.

If the physical examination reveals bodily damage from a habit behavior, focus on treating the specific injury and reducing or eliminating the immediate physical harm the child may be inflicting on himself or herself. At this time, consultation with a developmental-behavioral pediatrician, child psychologist, or child psychiatrist may be indicated.

Dental occlusal splints are occasionally used in the treatment of oral destructive habits. Splints do not eliminate but do help reduce the frequency of bruxism. Helmets may be required for children with severe and persistent head banging, particularly those with clinically significant developmental disabilities.

Drug therapy for stereotypies is only considered after behavioral assessment and interventions have been tried. They are not indicated in the management of common or primary complex motor stereotypies, because no significant benefit is evident.

Behavioral Therapy

Behavior therapy is the mainstay of treatment for children with habit behaviors. However, mixed results have sometimes been noted with common stereotypies.[14, 16, 24] Interventions can be directed at the antecedents or the consequences of the behavior.[25] For example, gloves or adhesive plasters can remove the antecedent stimulus for thumb sucking.

Effective behavioral therapies for habits include the following:

  • Habit reversal with differential reinforcement - This is a common strategy in which the child is made aware of the stimulus and is taught to make a competing response that is physically incompatible with the stereotypy (eg, in thumb sucking, having the child fold his or her arms when the stereotypy occurs); because of its brevity, immediacy, efficacy, durability, flexibility, and consistency, it is the most consistently effective way to treat presenting habits in children

  • Relaxation training

  • Self-monitoring

  • Reinforcement

  • Nocturnal biofeedback (for bruxism)

  • Competing responses

  • Use of bitter-tasting substances (for nail biting)

  • Negative practice

  • Use of aversive-tasting substances (for thumb sucking)

In complex motor stereotypies, behavioral methods have yielded variable results.[26] Significant improvement has been shown in primary complex motor stereotypies after 1 year. However, a clear improvement has not been confirmed for secondary stereotypies.

Overall, behavioral methods are most successful when patients are cooperative and motivated, regardless of the type of stereotypy present.

Pharmacologic Therapy

Most common habits in children that require treatment can be substantially improved by means of behavioral interventions, without the use of medication. However, in some cases, pharmacotherapy may have to be added to behavioral therapy in order to attain optimal treatment outcomes. When pharmacotherapy is considered, psychologists and medical physicians, such as child and adolescent psychiatrists or behavioral pediatricians, must work in consultation.

Naltrexone, an opioid antagonist, is believed to block the euphoria from self-injurious behaviors and other stereotypies. It has been shown to reduce the frequency of stereotypies in children with autism.[27] Clomipramine, a tricyclic antidepressant (TCA) that causes inhibition of serotonin reuptake, has also been used successfully in secondary stereotypies.[28] There is less evidence for the use of selective serotonin reuptake inhibitors (SSRIs).

A Cochrane review of 5 double-blind placebo-controlled studies comparing drug interventions with placebo for treatment of self-injurious behavior in adults with intellectual disability found only weak evidence to suggest that any active drug was more effective than placebo in this population.[29] No definite conclusions were reached regarding the benefits of naltrexone or clomipramine relative to placebo in this setting.

Although few drug studies of the many habits and habit disorders in children and adults have been performed, medications commonly used to treat other disorders (eg, tics, trichotillomania, and obsessive-compulsive disorder) may also be useful when pharmacotherapy for a childhood habit is indicated.

SSRIs and TCAs have shown some efficacy in reducing the frequency and intensity of some repetitive behaviors. SSRIs may be preferred to TCAs because of their milder adverse-effect profiles.

Other isolated successes have also been reported with traditional and newer neuroleptics. Neuroleptics have been shown to reduce stereotyped behaviors in patients with intellectual disability.[30] However, an adverse effect of these agents is tardive dyskinesias, and their use is therefore discouraged.

Special considerations with antidepressants

Physicians considering the use of antidepressants to treat pediatric patients are advised to be aware of the following information and use appropriate caution.

In December 2003, the UK Medicines and Healthcare Products Regulatory Agency (MHRA) issued an advisory that most SSRIs are not suitable for use by persons younger than 18 years for treatment of depressive illness. After review, the MHRA decided that the risks to pediatric patients outweigh the benefits of treatment with SSRIs, except in the case of fluoxetine, which appears to have a positive risk-benefit ratio in the treatment of depressive illness in patients younger than 18 years.

In October 2003, the US Food and Drug Administration (FDA) issued a public health advisory regarding reports of suicidality in pediatric patients being treated with antidepressant medications. This advisory reported suicidality (both ideation and attempts) in clinical trials of various antidepressant drugs in pediatric patients. The FDA asked that additional studies be performed because suicidality occurred in both treated and untreated patients with major depression and therefore could not be definitively linked to drug treatment.

A study of more than 65,000 children and adults treated for depression between 1992 and 2002 by the Group Health Cooperative in Seattle found that suicide risk declines, not rises, with the use of antidepressants. To date, this is the largest study to address this issue.

The currently available evidence does not indicate that the use of SSRIs to treat obsessive-compulsive disorder and other anxiety disorders is associated with an increased risk of suicide.

Consultations

A developmental-behavioral pediatrician, a child psychologist, or a child psychiatrist should be consulted for further assessment and possible treatment modalities as indicated.

For self-injurious stereotypies, a behavioral therapist should be consulted. For secondary stereotypies, the involvement of developmental pediatricians, pediatric neurologists, and psychiatrists may be appropriate, depending on the cause of the disorder.

 

Medication

Medication Summary

Most common habits in children that require treatment can be substantially improved by means of behavioral interventions, without pharmacotherapy. However, in some cases, medication in addition to behavioral treatments may be required to attain optimal treatment outcomes. Agents that may be used include selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs).

Antidepressants, SSRIs

Class Summary

SSRIs are antidepressant agents that are chemically unrelated to the tricyclic, tetracyclic, or other available antidepressants. They inhibit central nervous system (CNS) neuronal uptake of serotonin; they may also have a weak effect on norepinephrine and dopamine neuronal reuptake.

SSRIs are greatly preferred to the other classes of antidepressants. Because SSRIs have a less prominent adverse-effect profile than other agents do, their use promotes compliance. SSRIs do not have the risk of cardiac arrhythmia associated with TCAs. The risk of arrhythmia is especially pertinent in overdose, and a suicide risk must always be considered when a child or adolescent with a mood disorder is being treated.

Fluoxetine (Prozac)

Fluoxetine selectively inhibits presynaptic serotonin reuptake with minimal or no effect on norepinephrine or dopamine reuptake. It is approved for obsessive-compulsive disorder in children aged 8 years or older.

Sertraline (Zoloft)

Sertraline selectively inhibits presynaptic serotonin reuptake. It is approved for obsessive-compulsive disorder in children aged 6 years or older.

Fluvoxamine (Luvox CR)

Fluvoxamine is a potent selective inhibitor of neuronal serotonin reuptake. It does not notably bind to alpha-adrenergic, histamine, or cholinergic receptors and therefore has fewer adverse effects than TCAs do. It is approved for obsessive-compulsive disorder in children aged 8 years or older.

Paroxetine (Paxil, Pexeva)

Paroxetine is a potent selective inhibitor of neuronal serotonin reuptake. It also has a weak effect on norepinephrine and dopamine neuronal reuptake. It is approved for obsessive-compulsive disorder.

For maintenance dosing, make dosage adjustments to maintain patient on lowest effective dosage, and reassess patient periodically to determine need for continued treatment.

Citalopram (Celexa)

Citalopram use is off-label. Citalopram enhances serotonin activity due to selective reuptake inhibition at the neuronal membrane.

Escitalopram (Lexapro)

Escitalopram use is off-label. This agent is a selective serotonin reuptake inhibitor (SSRI) and an S-enantiomer of citalopram that is used for the treatment of depression. Escitalopram enhances serotonin activity because of selective reuptake inhibition at the neuronal membrane. Its mechanism of action is thought to be the potentiation of serotonergic activity in the central nervous system (CNS) through the inhibition of CNS neuronal reuptake of serotonin.

Antidepressants, TCAs

Class Summary

TCAs are structurally related to the phenothiazine antipsychotic agents and have 3 major pharmacologic actions, in varying proportions:

- Inhibition of the amine pump

- Sedation

- Peripheral and central anticholinergic action

These drugs inhibit the reuptake of norepinephrine or serotonin at the presynaptic neuron.

Clomipramine (Anafranil)

Clomipramine is a dibenzazepine compound belonging to the TCA family. It affects serotonin uptake, and its metabolite, desmethylclomipramine, affects norepinephrine uptake. It is approved for obsessive-compulsive disorder in children aged 10 years and older.

Opioid Reversal Agents

Class Summary

Opioid antagonists may block the euphoria from self-injurious behaviors and other stereotypies.

Naltrexone (ReVia, Vivitrol, Depade)

Naltrexone is an opioid receptor competitive antagonist with high affinity for mu receptors. It may diminish the euphoria effects resulting from endogenous opioidlike agents released during self-injurious behavior.