We have all heard of Autism Spectrum Disorder, but what is it? Who is at risk? How can we manage this disorder? Can we treat it? This article will answer all your questions.
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that affects an individual’s behavior, social interaction, and communication. ASD is characterized by unusual and repetitive sensory and motor behavior. The needs and abilities of autistic individuals may evolve over time and it can impact the person's employment and education opportunities as well as their family. Originally ASD was thought to be a rare childhood disorder, but now it is considered a common, lifelong condition.1
Causes of autism spectrum disorder
Despite the growing prevalence of ASD, the etiology of the disorder remains unclear. Nevertheless, research has revealed several risk factors that potentially contribute to ASD development.
The probability of an individual having ASD is much higher for families with a history of the disorder. This suggests that there might be a strong genetic component to ASD development. In fact, twin studies have reported that 74-93% of ASD risk is heritable.2
Sibling studies have revealed that when the first child is born with ASD the chance of the second child having ASD is 7-20%. 3
Several genes have been identified and associated with ASD, including CHD8, SHANK3, and NALCN.4 However, these disrupted genes are found in less than 0.5% of individuals with ASD.
It is important to keep in mind that ASD is a complex condition, and one should not rule out how the interaction of these genetic factors with environmental facts can play a significant role in ASD development.
Research has suggested several prenatal and perinatal factors that may influence ASD development such as lifestyle and maternal dietary factors.5 Short intervals between pregnancies (less than 24 months) as well as advanced parental age can increase the risk for ASD.6,7,8,9 Moreover, there are certain factors during the pregnancy period that may contribute to the development of ASD, such as maternal weight gain, metabolic conditions, hypertension, and infections.10
Multiple studies have revealed that exposure to certain medication (e.g. valproic acid) during pregnancy has been linked with higher risk of ASD.11 Other factors that have been associated with increased ASD risk are low birthweight (less than 1500 g) as well as preterm birth (less than 32 weeks).12
While the exact cause of ASD is not yet fully understood, research over the years has demonstrated various potential risk factors that may be associated with ASD development. These include genetic and environmental factors and disruptions in normal brain development.1
Signs and symptoms of autism spectrum disorder
ASD is a developmental disability that results from differences in the brain. Studies have shown that in early development individuals with ASD have enlarged brain volume. The birth head size of individuals with ASD at 12 months is slightly larger than control individuals at the same age and the average brain volume of individuals with ASD is increased at 18-35 months.13 Similar results have been demonstrated for ASD individuals at the age of 10.14
Although each person with ASD is unique, there are common symptoms that characterize the disorder irrespective of ethnicity, culture, and race. The core features are repetitive and restricted behaviors (sensory and motor) and social communication.15
Note that not all individuals with ASD have all the behaviors but some of the most common are listed below.
One of the most common signs of ASD is social interaction difficulties. Individuals may struggle to maintain eye contact and understand social cues. They often prefer to be on their own, and it is hard for them to make friends. They struggle to understand others’ perspectives and emotions and they cannot express their own feelings. Some people do not respond to their names and struggle to listen or look at people when talking.
Another common symptom of ASD individuals is communication difficulties. There is a delay in language development, and they struggle to maintain conversations. They don’t talk a lot and some individuals may have repetitive and unusual speech patterns and speak in a monotone voice.
ASD individuals may show repetitive and unusual behaviors such as repetitive movements (spinning, flapping or licking their fingers), or repetitive routines. They get very upset if their daily routine changes. They may have an interest in specific topics (weather, trains, etc.) to the extent that they can become fixated on these interests.
They may have sensitivity to certain textures, sounds, smells, or even avoidance of physical touch.
Individuals with ASD may have other related characteristics such as unusual eating habits and emotional reactions.
Although ASD individuals may have irritability or sleep problems, individuals who are on the spectrum of ASD may have various strengths. For instance, they may be strong auditory or visual learners, excellent in art, mathematics, science, or music, and have exceptional memory in remembering things over long periods.
Management and treatment for Autism Spectrum Disorder
There is no currently known cure for ASD, however, early intervention with a comprehensive treatment plan can result in substantial outcome improvement in individuals with ASD. There are several approaches currently available for the management of the disorder which mainly seek to reduce symptoms interfering with people’s daily functioning. ASD does not affect all people in the same way. Depending on the strengths and challenges one faces, one may need different treatment. Therefore, multiple professionals may be involved in the treatment plan of an individual. Treatments can be provided in multiple settings including home, education, community, health, or even a combination of all.
Treatment strategies can be broken down into specific approaches.
This approach focuses on improving developmental abilities and skills such as language and speech.
The most widely used therapy is speech and language therapy which aids in the enhancement of language use and understanding.
Another therapy used is occupational therapy which helps people improve their responses to sensory stimuli.
Physical skills like finger or body movements are improved with physical therapy.
This approach aims to help the individual understand the consequences of a behavior. This kind of therapy has been proven very effective in reducing ASD symptoms and has been adopted by schools and treatment clinics. A common behavioral treatment is Applied Behavior Analysis (ABA). This treatment improves various skills by discouraging undesired behaviors and encouraging desired ones.
This treatment aims at building emotional bonds and strengthening social skills. In this approach, parents are encouraged to support and follow their child’s interests so they can build communication with them. This approach also uses a strategy that helps individuals develop expectations of social situations called social stories.
This approach involves a classroom setting. One type of educational approach is the Treatment and Education of Autistic and Related Communication-Handicapped Children (TEACCH). It focuses on visual learning and consistency. Teachers learn to adjust the learning structure in order to improve academic outcomes. For instance, forming learning stations and setting boundaries, or learning to draw a daily routine. Instead of giving instructions verbally, teachers can replace that with physical demonstrations or visual instructions.
This approach helps people deal with mental health issues (anxiety, depression, etc.). An example is cognitive behavioral therapy (CBT) which enforces learning of connections between behaviors, thoughts, and feelings.
Medications are used to treat symptoms of ASD and make the individual function better, but not to treat ASD itself. Medications can help with energy, focus, and self-harm management. Furthermore, medications are used to manage stress, anxiety, and sleeping problems.
Complementary and alternative treatments
. This strategy can be used alongside the other approaches and includes herbal supplements, diets, relaxation therapy, art/animal therapy, or mindfulness techniques.
How is Autism Spectrum Disorder diagnosed?
ASD diagnosis may be difficult since there is no medical test, but early diagnosis is critical for young people to receive appropriate care. ASD results from changes in the development of the brain and neural organization, however the diagnosis is made based on the behavior, since there are no biomarkers to track these neural changes. A reliable diagnosis can be made at the age of two, but many young children receive a final diagnosis when they are older.1,16
The American Academy of Pediatrics (AAP) suggests that all children should receive developmental delays screening at 9, 18, 24, and 30 months. People with higher likelihood of ASD may receive further screening. This includes children :
- With older parents
- With genetic predispositions
- Who were born prematurely
- Who had a low birth weight
The APP also recommends that children should receive autism screenings at 18 and 24 months. If the child presents behavioral problems, further evaluation is needed.
The diagnostic evaluation includes a variety of examinations to assess the person’s cognitive and language abilities, behavior, development and everyday life. These examinations are carried out by a team of specialists including neurologists, child psychologists, speech-language pathologists, psychiatrists, pediatricians, occupational therapists, and educational specialists. This evaluation together with some blood and hearing tests may lead to a formal diagnosis.17
Receiving a correct diagnosis either as a child or as an adult can help an individual identify their strengths, challenges, and personal needs to develop the proper treatment plan.
How can I prevent ASD?
Although the exact causes of ASD are not known, research has identified several factors that could potentially increase the risk of developing the condition. There are various steps that can be taken by individuals and their families to reduce this risk and improve the outcomes:
- Regular perinatal care can aid in the early identification of health issues such as avoiding exposure to harmful substances or following a healthy diet
- One of the most important steps is early intervention and referring to therapy, support, and educational programs if you suspect your child has ASD
- A healthy lifestyle (diet and activity) can help the brain’s development and overall quality of life
- Reducing chronic stress since it can severely impact the development of the brain and therefore one should find healthy stress management methods like meditation, or therapy
- Individuals with ASD should receive regular medical care
Note that the aforementioned steps could help reduce the risk of ASD but they are not guaranteed to prevent the disorder.17
Who is at risk of ASD?
There are several risk factors for ASD:
- Family history of ASD
- Prenatal exposure to alcohol, drugs, chemicals
- Advanced parental age (especially in fathers)
- Premature birth or low birth weight
- Medical conditions (Down’s Syndrome, Fragile X syndrome)
These factors may increase the risk of developing ASD, but it is not guaranteed. Understanding who is at risk of ASD may help families take steps to improve the outcomes of the disorder.17
How common is ASD?
Current estimates have shown the prevalence of ASD in developed countries is around 1.5%.9 The World Health Organization has estimated that about 1 out of 100 children has ASD, however, these estimates may vary across studies. The prevalence of ASD in low-income countries is unknown. These disparities are due to many factors including healthcare access, cultural attitudes toward autism, and unequal resource distribution.
According to the Centers for Disease Control and Prevention, the prevalence of ASD is higher in people assigned male at birth (PAMAB) than people assigned female at birth (PAFAB), with 1 in 34 PAMAB having ASD compared to 1 in 144 PAFAB.
Understanding the prevalence of the disorder is crucial for addressing disparities in certain populations and developing strategies to ensure individuals receive the appropriate care and support.
When should I see a doctor?
A significant difference can be made in the lives of people with ASD and their families if we identify the disorder early. Some infants may show signs before the age of two including:
- Delayed speech development
- Reduced eye contact
- No interest in social interaction
If a parent notices these symptoms they should contact the doctor as soon as possible. Visiting a doctor at the right time can substantially help in the quality of life the individual will have.17
In conclusion, ASD is a complex neurodevelopmental disorder affecting communication, social interaction, and behavior. The causes are not well understood but are thought to be a combination of genetic and environmental factors. Signs and symptoms of ASD can vary between people, but an early diagnosis can help people lead a fulfilling life. Preventing this disorder is not possible but correct management of the disorder can make a significant difference in a person’s life.
- Lord C, Elsabbagh M, Baird G, Veenstra-Vanderweele J. Autism spectrum disorder. Lancet [Internet]. 2018 Aug 11 [cited 2023 Jul 10];392(10146):508–20. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398158/
- Tick B, Bolton P, Happé F, Rutter M, Rijsdijk F. Heritability of autism spectrum disorders: a meta‐analysis of twin studies. J Child Psychol Psychiatry [Internet]. 2016 May [cited 2023 Jul 10];57(5):585–95. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4996332/
- Messinger D, Young GS, Ozonoff S, Dobkins K, Carter A, Zwaigenbaum L, et al. Beyond autism: a baby siblings research consortium study of high-risk children at three years of age. J Am Acad Child Adolesc Psychiatry [Internet]. 2013 Mar [cited 2023 Jul 10];52(3):300-308.e1. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625370/
- Yuen RK, Merico D, Bookman M, Howe JL, Thiruvahindrapuram B, Patel RV, et al. Whole genome sequencing resource identifies 18 new candidate genes for autism spectrum disorder. Nat Neurosci [Internet]. 2017 Apr [cited 2023 Jul 10];20(4):602–11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5501701/
- Mandy W, Lai MC. Towards sex- and gender-informed autism research. Autism [Internet]. 2017 Aug [cited 2023 Jul 10];21(6):643–5. Available from: http://journals.sagepub.com/doi/10.1177/1362361317706904
- Zerbo O, Yoshida C, Gunderson EP, Dorward K, Croen LA. Interpregnancy interval and risk of autism spectrum disorders. Pediatrics [Internet]. 2015 Oct [cited 2023 Jul 10];136(4):651–7. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586728/
- Idring S, Magnusson C, Lundberg M, Ek M, Rai D, Svensson AC, et al. Parental age and the risk of autism spectrum disorders: findings from a Swedish population-based cohort. International Journal of Epidemiology [Internet]. 2014 Feb 1 [cited 2023 Jul 10];43(1):107–15. Available from: https://academic.oup.com/ije/article-lookup/doi/10.1093/ije/dyt262
- Lyall K, Croen L, Daniels J, Fallin MD, Ladd-Acosta C, Lee BK, et al. The changing epidemiology of autism spectrum disorders. Annu Rev Public Health [Internet]. 2017 Mar 20 [cited 2023 Jul 10];38:81–102. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566093/
- Sandin S, Hultman CM, Kolevzon A, Gross R, MacCabe JH, Reichenberg A. Advancing maternal age is associated with increasing risk for autism: a review and meta-analysis. Journal of the American Academy of Child & Adolescent Psychiatry [Internet]. 2012 May [cited 2023 Jul 10];51(5):477-486.e1. Available from: https://linkinghub.elsevier.com/retrieve/pii/S089085671200144X
- Lyall K, Ashwood P, Van de Water J, Hertz-Picciotto I. Maternal immune-mediated conditions, autism spectrum disorders, and developmental delay. J Autism Dev Disord [Internet]. 2014 Jul [cited 2023 Jul 10];44(7):1546–55. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104679/
- Christensen J, Grønborg TK, Sørensen MJ, Schendel D, Parner ET, Pedersen LH, et al. Prenatal valproate exposure and risk of autism spectrum disorders and childhood autism. JAMA [Internet]. 2013 Apr 24 [cited 2023 Jul 10];309(16):1696–703. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511955/
- Lampi KM, Lehtonen L, Tran PL, Suominen A, Lehti V, Banerjee PN, et al. Risk of autism spectrum disorders in low birth weight and small for gestational age infants. J Pediatr [Internet]. 2012 Nov [cited 2023 Jul 10];161(5):830–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3449022/
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- Zwaigenbaum L, Bauman ML, Fein D, Pierce K, Buie T, Davis PA, et al. Early screening of autism spectrum disorder: recommendations for practice and research. Pediatrics [Internet]. 2015 Oct [cited 2023 Jul 10];136(Suppl 1):S41–59. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9923900/