This post is part of a series of guest posts on GPS by the graduate students in my Psychopathology course. As part of their work for the course, each student had to demonstrate mastery of the skill of “Educating the Public about Mental Health.” To that end, each student has to prepare two 1,000ish word posts on a particular class of mental disorders.
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What is Stereotypic Movement Disorder? by Kati Embry
Stereotypic movement disorder is a psychological phenomenon that was first described during the early 1900s. During this time the symptoms of this disorder were attributed as a psychiatric disorder. Since then, the symptoms of stereotypic movement disorder have been recognized as both a psychological and neurological issue.
Stereotypic movement disorder can best be described as a disorder based on repetitive, purposeless activities or movements that interfere with the functions of daily life and may also result in physical harm or injury. Common repetitive behaviors may include thumb or hand sucking, body rocking, head banging, nail biting, trichotillomania, and bruxism. Complex motor stereotypies include flapping, waving, opening and closing of the fist, finger wiggling, wrist flexion and extension, and atypical gazing at objects or fingers, abnormal pacing running and skipping. The below video illustrates this.
Stereotypic movements generally first begin before the age of three years old. Simple movements are common in infants and toddlers with approximately 15-20% displaying some type of repetitive movement. Children with complex stereotypic movements will exhibit approximately 80% of symptoms before the age of two, 12% between two and three, and 8% over the age of three. These stereotypic movements can occur at any age, but are easier to identify in adolescence.
Stereotypic movement disorder can be caused by sensory deprivation, such as deafness or blindness; the use of certain drugs like cocaine or amphetamines; brain diseases from seizures or infections; major psychiatric disorders such as anxiety disorder, obsessive-compulsive disorder, or autism; or intellectual disabilities. Research has also suggested that inadequate parenting can increase the risk of a child developing stereotypic movement disorder.
Diagnostic Criteria
Individuals with stereotypic movement disorder will often injure themselves.
The following criteria are required for a diagnosis of stereotypic disorder to be given:
- Repetitive, purposeless motor behavior; such as body rocking, head banging, self-biting, or hand shaking or waving
- The repetitive motor behavior must interfere with social, academic, or other daily activities and may result in physical injury.
- Onset of symptoms occur during the early developmental period
- The repetitive motor behavior is not due to physiological effects of a substance or neurological conditions. It also cannot be better explained by another neurodevelopmental or mental disorder such as trichotillomania or obsessive-compulsive disorder.
Signs
Most common childhood habits are not severe and have no specific observable physical signs, only the observable movements themselves. Signs for stereotypic movement disorder may include the following: thumb and hand sucking, nail biting, nose picking, bruxism, breath-holding spells, and head banging. Thumb and hand sucking can be a sign if the behavior is continued past the age of 4-5 years, dental problems occur, there is an increased risk of accidental ingestions and pica, thumb callus and skin breakdown, deformities of the fingers and thumbs, ot paronychia. Nail biting can be a sign is the child has extremely short fingernails, paronychia, oral herpes, herpetic whitlow, damaged dentition, apical root resorption, fractures to the incisors and gingivitis. Nose picking can be a sign if there is epistaxis, perforation of the nasal septum or infection. Bruxism can be a sign if there is 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, or recurrent headaches. Breath-holding spells is a sign if the child experiences an injury from falling or seizures. Head banging is a sign if there is callus formation, abrasions, contusions, skull fractures, eye injuries, or dental injuries.
Prevalence
Complex stereotypic movements are less common and have a prevalence rate of 3%-4%. Approximately 4%-16% of individuals with intellectual disabilities engage in stereotypic behavior and self-injury. Individuals with severe intellectual disabilities living in residential facilities have a greater prevalence rate between 10%-15% of stereotypic
Risk Factors
There are several factors that can increase a child’s likelihood of developing stereotypic movement disorder. These include environmental, genetic, and physiological factors. Social isolation is a huge risk factor for self-stimulation that may result in repetitive self-injury. Environmental stressors and fear may also trigger stereotypic movement behaviors. Cognitive functioning that is below normal for the child’s age is associated with an increased risk for developing stereotypic behaviors and a decreased response to interventions. Individuals with moderate to severe intellectual disabilities are at a higher risk for developing stereotypies. There is no cultural difference in stereotypic movement disorder. It occurs in all races and cultures. However, there may be differences in the tolerance and attitudes exhibited towards those with stereotypic movements and this may result in delayed diagnosis.
Treatment
There are two main forms of treatment available to those with stereotypic movement disorder: behavioral therapy and pharmacologic therapy. Behavioral therapy is the primary option used to help treat the stereotypic movement behaviors. If the behavioral therapy is effective, there will be a reversal in habits with the use of differential reinforcement. With this approach the child is made aware of the stimulus and learns to perform a response that competes with the stereotypic movement. An example of this would be a child crossing or folding their arms to prevent them from sucking on their thumb. This is approach is the most consistent way to effectively deter the movements.
Behavioral therapy also includes relaxation training, self-monitoring, reinforcement, nocturnal biofeedback, competing responses, use of bitter tasting substance for nail biting, negative practice, and the use of aversive-tasting substances for thumb sucking. The majority of children can be effectively treated with behavioral interventions, without the use of medication. However, some cases may require the use of medication in addiction to behavioral therapy to attain optimal treatment outcomes.
Pharmacological therapy involves the use of medication to help treat symptoms. When this treatment option is considered, psychologists and medical physicians work together in consultation. One successful medication is Naltrexone, an opioid antagonist, which helps block the euphoria from self-injury and other harmful behaviors. Another medication that can be used to help treat stereotypic movement disorder is Clomipramine, a tricyclic antidepressant, which helps cause inhibition of serotonin reuptake.
