More and more kids with Down syndrome are being diagnosed with autism or autistic syndrome disorder (ASD). Autism Research 7 from the U.K. suggested that about 16 to 19 percent of children with Down syndrome also have ASD while some 8 to 9 percent have autism. Other researchers have deemed higher rates associated to this dual diagnosis.
According to the National Down Syndrome Society, one in every 691 babies in the United States is born with Down syndrome, deeming Down syndrome the most common genetic condition. Approximately 400,000 Americans have Down syndrome and about 6,000 babies with Down syndrome are born in the United States each year.
Autism spectrum disorder (ASD), on the other hand, is a range of complex neurodevelopment disorders, essentially characterized by social impairment, communication challenges and restricted, repetitive and stereotyped patterns of behavior. Autistic disorder, sometimes known as autism or classical ASD, is the most severe form of ASD. Experts believe that one out of 88 children, aged 8, have ASD (Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report, March 30, 2012).
Previously, the diagnosis of autism in children with Down syndrome has been questioned because of the presence of cognitive impairments in these individuals. Autistic behaviors are difficult to differentiate from repetitive behaviors, communication difficulties and other cognitive delays associated with intellectual disability. Due to these challenges, physicians often hesitate to diagnose ASD in children with Down syndrome, leaving them devoid of important therapy and educational services.
A study from the Journal of Applied Research in Intellectual Disabilities evaluated a large sample of 183 participating children diagnosed with autism and Down syndrome. Children with both Down syndrome and ASD demonstrated less impairment on the Communication Domain in imitation, use of gestures and imitative social play than individuals with just ASD. Children with Down syndrome and ASD showed less impairment in eye gaze, social smiling, shared enjoyment, offering comfort, social overtures and response to other children’s social approaches, on the Reciprocal Social Interaction Domain as well. However, when it came to the Restricted, Repetitive and Stereotyped Patterns of behavior, the only difference to stand out was a greater tendency of demonstrating compulsions or rituals by the children with Down syndrome than the other children with ASD. Otherwise, the behaviors were similar to others with autism.
Common symptoms of this dual diagnosis include refusing food, receptive problems such as hearing, repetitiveness in speech and motor behaviors, unusual response to sensations and disruptive behavior. Other medical conditions may also accompany these behavioral symptoms such as seizures, dysfunctional swallowing, nystagmus (a constant movement of the eyes) or severe hypotonia (low muscle tone).
Why some children have ASD alongside Down syndrome is still largely unclear. In an interview with the Interactive Autism Network (IAN), George T. Capone, M.D., director of the Down Syndrome Clinic at the Kennedy Krieger Institute in Baltimore, Maryland, explained, “No one really knows the answer to that….Some think it is related to some of the co-occurring medical conditions. That would probably be true in the case of infantile spasms, a type of epilepsy seen in very young children, which are associated with autism spectrum behaviors as a long-term outcome. It would appear that whatever the mechanism, it is related to the way the genes on Chromosome 21 interact with other genes on the other 22 pairs of chromosomes, resulting in a differently-organized brain compared to typically-developing children with Down syndrome.”
If a child with Down syndrome is suspected of having ASD or any other condition qualifying as a dual diagnosis, it is important for him or her to be examined by a professional with sufficient experience evaluating children with cognitive impairment. Dr. Capone believes DS-ASD may share symptoms with stereotypy movement disorder, depression, post-traumatic stress disorder, obsessive-compulsive disorder, anxiety disorder or when children are exposed to extremely stressful and chaotic events or environments.
Sometimes children with Down syndrome might be experiencing unclear medical problems such as an earache, headache, toothache, sinusitis, gastritis, ulcer, pelvic pain and glaucoma. Such situations might result in autistic-like behaviors such as irritability, aggression or self-hurting behavior. Hence, a detailed medical history and physical examination is vital to understand other reasons for the behavior.
Additionally, an Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS) or the Gilliam Autism Rating Scale (GARS) are completed by the parents to be then scored and considered along with clinical observation to determine if a child has ASD.
Dr. Capone said, “It is difficult to tease apart the atypical social communication and poor reciprocity part of autism from other aspects of intellectual disability that we see in Down syndrome. This makes diagnosing ASD in a child with Down syndrome problematic. Another reason could be that the possibility that a child with Down syndrome could also have ASD is not thought of frequently enough yet.”
Furthermore, discussing the ramifications of a misdiagnosis, Capone said, “The biggest implication is for the early intervention program and the Individualized Education Program (IEP) because these children need something above and beyond standard interventions for developmental delay, such as addressing maladaptive behaviors, deficits in functional communication and daily living skills. Another aspect of having an autism diagnosis is that it should put people on high alert for other conditions such as sleep problems, anxiety and mood disorders and, of course, maladaptive behaviors generally.”
Another U.K. study in 2013 reported that compulsive behaviors, ritualistic behavior and restricted preferences were as common in children with Down syndrome without ASD as in those with ASD. These behavioral traits could lead to incorrect diagnoses of ASD for some children with Down syndrome. When children with Down syndrome and ASD are compared to children with Down syndrome who do not have ASD, the children with Down syndrome and ASD are likely to be more severely cognitively delayed and to exhibit more behavior difficulties.
Various challenges associated with the diagnosis of DS-ASD include failure to recognize a dual diagnosis, confusion with other behavioral and psychiatric conditions like attention deficit hyperactivity disorder (ADHD) or OCD, often a lack of acceptance of the co-occurrence of the two conditions on the physicians’ part and that of the parents.
As far as the medication is concerned, Dr. Capone believes in caution when it comes to using stimulants or antidepressants for such children. For children with a high degree of impulsive and disruptive behavior, medications for ADHD can be used. Atypical antipsychotic medications can be used for a high degree of cognitive and attentional disorganization. Mood stabilizers for very irritable and self-injurious behavior may come in handy, especially in case of a history of infantile spasms. No matter which kind of medication is administered, they are adjusted frequently according to the child’s individual needs and any negative side effects.
Essentially, treatment is a combination of various interventions whether it’s medication, behavioral support or functional communication.
There is still a lot to be learned about children with DS-ASD. Meanwhile, parents must educate themselves about this condition. Research efforts must move towards specific markers in the development of the brain, which can distinguish DS-ASD from Down syndrome and autism, and the possible benefits of various treatments need to be more carefully documented.
The Dual Diagnosis Helpline is available at your service 24/7 to help you through the complex dynamics of dual diagnosis and guide you towards the treatment that is best suited to your needs. If you or a loved one is currently seeking therapy, call us right now at 855-981-6047.