Down Syndrome (DS) is the most common chromosomal condition in the United States, affecting about 1 in every 700 babies (CDC). This condition is also known as Trisomy 21, due to there being an extra copy of chromosome 21 (CDC). This extra chromosome results in changes in the development of the brain and body, which in turn can lead to cognitive and physical challenges (CDC). Some hallmark physical characteristics include almond shaped eyes that slant up, smaller hands and feet, shorter stature, small ears, and a flattened face, particularly near the bridge of the nose (CDC).
Individuals with DS usually have and IQ of mild to moderately low range, however, there is a large continuum of functioning within the population (CDC). DS is co-morbid with other major birth defects including hearing loss, sleep apnea, ear infections, eye diseases, and heart defects (CDC). Babies with DS are 24 times more likely to die in the first 28 days of life compared to counterparts without DS. Also, there is a positive correlation between a mother’s age during pregnancy and the development of DS (CDC). By the time a woman reaches age 40, the prevalence of having a baby with DS is 1. 2% (CDC).
While DS is a life-long condition, the early intervention of services such as physical, occupational, and speech therapy can allow the child to develop their full potential (CDC). Individuals with developmental disabilities (DD) are three to four times more likely to suffer from a psychiatric illness (source 3). OCD is one of the most common mental illnesses affecting individuals with DS (source 3). There is a hypothesis that people with DS and comorbid OCD would be more likely to experience a traumatic life event before developing OCD than individuals with another DD and co-morbid OCD (source 3).
People with DS are more vulnerable to developing OCD, depressive or PTSD symptoms following traumatic experiences (source 3). A genetic predisposition, premorbid functioning and the presence of the traumatic events may play an important role in these patients’ vulnerability (source 3). Another risk factor for developing OCD is the presence of serotonergic and dopaminergic abnormalities (source 3). These abnormalities directly relate to the processing and understanding of emotional events, so the potential for abnormality aligns with a higher risk of adverse reactions to trauma (source 3).
While individuals with DS are more likely to have OCD, it is clear that not all repetitive behaviors displayed are indeed OCD. (source 3) The clinical presentation of OCD in individuals with DS can vary, depending on the underlying intellectual capacity (source 2). This results in caretakers sometimes assuming the behaviors are part of the DS diagnosis itself, resulting in not seeking help from a professional (source 2). In school settings children with DS are described as engaging in “repetitive, ritualistic, compulsive like” and “perfectionistic” behaviors (source 1).
Repetitive behaviors can be described as “behaviors characterized by frequency, repetition, inappropriateness, and invariance” including “stereotyped and self-injurious” behaviors (Source 5). Repetitive behavior and restricted interests (RBRI) exists as part of the repertoire of typical children and adults across cultures. (source 4) However, RBRI’s are more common in children with disabilities, including DS, Autism Spectrum Disorders (ASD), and Prader–Willi syndrome (PWS). Studies show that children with DS show similar mental age-related changes in compulsive/repetitive behavior as a comparison group without DS (source 1).
Younger children with and without DS exhibit more compulsive behaviors than older children (source 1). Also, children with DS display the same number of repetitive, ritualistic, and “Just Right” behaviors that are considered typical in early development (source 1). These behaviors exist on a continuum from “motoric repetitive behaviors (e. g. , stereotyped movements and self-injury) or lower-order repetitive behaviors to more complex behaviors (e. g. , ordering, checking, washing) or higher-order repetitive behaviors” (source 5).
Children with DS engage in more frequent intense repetitive behaviors at each mental level than their typically developing counterparts (source 1). The “Just Right” behaviors serve qualitatively different functions among children with DS opposed to children without (source 1). In typical children, these behaviors serve an adaptive role (source 1). In children with DS, they more frequently serve a maladaptive role (source 1). These maladaptive behaviors more closely resemble the sensory and perceptual phenomena found in Autism and OCD (source 1).
The compulsive behaviors are sufficiently time-consuming or preoccupying as to impede, rather than facilitate, adaptive behaviors of socialization and daily living skill (source 1). Sometimes they can be adaptive (reflecting organization and orderliness), but others are so limited and intense they resemble pathological trouble (source 1). The lower order repetitive behaviors are regarded as coping reactions. They can function to modulate stress or arousal, produce a pleasurable sensory stimulus or serve to remove unpleasant sensory stimuli, and do not typically interfere with a child’s daily living and occupations. source 5)
When higher order repetitions are disrupted, it results in high levels of stress and anxiety, which does result in a disruption of successful functioning. (source 5) Higher order repetitions can strongly resemble the compulsions seen in Obsessive-Compulsive Disorder (OCD) (source 5). Yet, there is distinct evidence for the distinction of the two. There is a difference in etiology for the emergence of obsessive-compulsive disorder in those with co-morbid developmental disabilities (source 3).
For example, diagnostic assessments for Autism consistency include a three-factor model which includes self-injurious behaviors, restricted stereotypical behavior, and compulsive ritualistic behavior. (source 5) OBSESSIVE-COMPULSIVE BEHAVIORS IN INDIVIDUALS WITH DOWN SYNDROME. It is believed that some repetitive behaviors are among the phenotype of DS (source 1). Further research is needed regarding the importance of cognitive factors in the phenomenology of compulsive-like behaviors (source 1).
Through recent research, it has been discussed that “anecdotal ‘stubbornness’ and high intensity of rigid behaviors reflect a rigid behavioral phenotype for children with DS” (source 1). While repetitive behavior is not considered a defining characteristic of Down syndrome, many individuals with Down syndrome display some form of repetitive behavior (source 5). It is important to recognize that the adaptive and maladaptive nature of repetitive behavior is subject to individual differences in health, environment, family, and other individual differences (source 4).
In this respect, the justification of the behavior needs to be considered holistically in terms of how it affects the individual (source 4). Children with DS show phenotypic strengths and weaknesses, including relative social strengths and high social motivation (source 5). However, it is not clear if this rigidity comes from a delay in flexibility that accompanies the cognitive development of individuals with DS. (source 1) There is evidence that higher-order repetitive behavior or ritualistic behavior can be maintained by automatic reinforcement among children with developmental disabilities. source 5).
However, interventions used with the DS population typically involve aversive procedures that are not informed by functional assessments (source 5). These include positive punishment taking the form of a visual cue, response blocking, and contingent demands (source 5). There are only a small number of studies that have been conducted on correcting repetitive behaviors in children with DS, and those that have focused primarily on lower-order behaviors (source 5).
In higher-order behavior scenarios, pharmacological methods are typically employed, however, no conclusive evidence of success has been derived (source 5). Alternative intervention strategies need to be explored in this population because current measures are not sufficient (source 5). One potential alternate strategy has been the use of positive procedures in addition to strictly punishment procedures (source 5). Positive procedures alone have been proven to reduce, but not eliminate, the occurrence of repetitive behavior among individuals with DS (source 5).
Part of this divide in functional assessment foundation in the DS population is due to differing etiologies of intellectual disabilities responding differently to interventions (source 5). Specific to DS, there is a lack of in-depth literature evaluation in regards to reinforcers associated with maintaining repetitive behaviors (source 5). A temporary strategy has been the utilization of Differential Reinforcement of Other Behavior (DRO), which has proven to be successful in reducing repetitive behavior in some cases for up to three months (source 5).
Determining a successful course of action is critical due to early repetitive behaviors predicting maladaptive behavior later in development (source 5, source 4). As the chronological and mental age of individuals with DS increases, compulsive behaviors become more highly correlated with problem behavior (source 5). Also, research supports some continuity between the normal manifestations of RBRI and those associated with many clinical conditions (source 4). This suggests some common underlying neurobiological mechanisms (source 4).
It has been found that neural networks that channel and sub-channel information from limbic to cortical regions (orbital, frontal, etc. ) are overactive in patients with OCD (source 1). This circuit is involved in error detection and the source of false brain messages indicating a threat when none is present (source 1). Also, this could be an explanation for attempting to resist the urge to engage in compulsive behaviors (source 1). These circuits link emotive elements with the formation of goal-directed behaviors, which is crucially involved in implicit learning.
These goal-directed behaviors are also altered in OCD (source 1). With medication and cognitive behavioral therapy (CBT) the operative brain area can be reduced (source 1). Research indicates that the subgroup of children with DS also present with clinically significant impairments in terms of social communication and restricted patterns of behaviors, such as those that characterize Autism Spectrum Disorders (ASD). (source 6) Children with DS and ASD were reported by teachers to exhibit more problem behaviors, self-absorbed behaviors, and poorer social relating than children with just a DS diagnosis. source 6)
Children with co-morbid DS and ASD, as well as a subgroup of non-specific developmental disabilities, has significantly higher scores than the group with DS only on overall repetitive behaviors. (source 6) In order to develop more appropriate screening and assessment procedures, efforts to describe the behavioral presentation of children with co-occurring DS and ASD is very valuable. (Source 6) This information could facilitate efficient access to appropriate intervention and support systems in school, leisure, and occupations. source 6)
It is also critically important when determining intervention plans, to examine the social validity of the intervention package, how it will be received by professionals, families, and communities (source 5). Many gaps still exist in research and treatment surrounding mental health concerns in people with DS. (source 7) More information is needed in regards to the types and prevalence of behaviors and emotional problems in children, adolescents, and adults with DS (source 7).
Researchers need to understand the development of RBRI to distinguish what is symptomatic and warranting clinical attention from those that are conspicuous by virtue of their relative asynchrony with other markers of developmental level (source 4). Overall, there is a need to dissect complicated biopsychosocial risks and protective factors that increase or decrease psychopathology. (source 7) Research on psychiatric status a well as diagnostic status needs to be linked across age groups to examine associated processes of sociability, anxiety and attention. source 7).
Long-term longitudinal studies are needed of typical and non-typical children to understand the nature of repetitive behavior (source 4). Moving forward, research needs to identify evidence-based treatment opportunities that aid in reducing distressful symptoms linked to repetitive behaviors (source 7). Decreasing the repetitive behavior among individuals with DS may create more opportunities for learning, decreased social stigmatization, and ultimately an increased quality of life (source 5).
