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Autism Spectrum Disorder

What is Autism Spectrum Disorder?

Autistic Spectrum Disorder (ASD) is a developmental disorder that causes brain differences that impact communication and social behavior. Symptoms generally develop in the first 2-3 years of life. ASD now encompasses a number of disorders formerly considered distinct. These disorders were autistic disorder, developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome. However, these conditions are now considered to be parts of a single spectrum known as Autistic Spectrum Disorder. The main features of ASD are difficulty in communication and social interaction, and restricted interests and repetitive behaviors. The severity and type of symptoms vary greatly among affected individuals.



  • Autism Spectrum Disorder

Autistic Spectrum Disorder (ASD) is a developmental disorder that causes brain differences that impact communication and social behavior. Symptoms generally develop in the first 2-3 years of life. ASD now encompasses a number of disorders formerly considered distinct. These disorders were autistic disorder, developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome. However, these conditions are now considered to be parts of a single spectrum known as Autistic Spectrum Disorder. The main features of ASD are difficulty in communication and social interaction, and restricted interests and repetitive behaviors. The severity and type of symptoms vary greatly among affected individuals.

Acknowledgement of Autism Spectrum Disorder has not been added yet.

The prevalence of ASD is around 1 in a hundred children. This number has been increasing over the past couple of decades. ASD affects males more than it affects females. However, the reason for this difference is not known. ASD appears to affect individuals from all socioeconomic, ethnic, and racial backgrounds equally.


Name Abbreviation
Autism Spectrum Disorder ASD

ASD is likely caused by a combination of genetic and environmental factors. Up to one-third of ASD cases can be associated with a genetic cause and many different genes have been identified that increase the risk of ASD. In some cases, another genetic disorder may be present such as Rett syndrome or fragile X syndrome. Human genetic material is organized into structures called chromosomes. Chromosome X is one of the two chromosomes that are responsible for determining the sex of the individual. Rett syndrome is a genetic brain disorder that is caused by a mutation in a gene on the X chromosome called Methyl CpG binding Protein 2 (MECP2) which is involved in the normal nerve cell function. Fragile X syndrome is another genetic condition that causes developmental issues and is a result of a mutation is the fragile X mental retardation 1 (FMR1) gene. FMR1 gene is also located on the X chromosome and encodes a protein that plays a role in regulating the connection or synapses between nerve cells. Other genes that may be involved include Chromodomain-helicase-DNA-binding protein 8 (CHD8) which encodes a protein that regulates gene activity and is vital during fetal development. While some associated genes can be inherited from parents, many are a result of new genetic changes in fetal cells. 


Environmental factors seem to have a stronger influence on the development of ASD during pregnancy. There is still debate about the environmental factors that increase the risk of ASD and their importance. However, some factors that are under investigation include maternal viral or bacterial infection during pregnancy, consumption of certain medications during pregnancy, parent’s age, and maternal antibodies. Antibodies are molecules produced by the immune system that attack foreign particles and organisms. There are some studies showing that a number of mothers of children with ASD have antibodies against proteins present in their fetus’ brain which could alter brain development. More research, however, is needed to further investigate this. 

ASD is a disorder that affects the brain. The regions of the brain that is behind the forehead (frontal lobe) and around the ears (temporal lobe) are most affected. The frontal lobe controls personality and many higher cognitive skills such as language, problem-solving, and decision-making. The temporal lobe is involved in speech recognition and processing. Recent studies have found evidence that a specific brain structure located in the temporal lobe called the amygdala may also be affected. The amygdala controls many social and aggressive behaviors. In addition, it has been found that the brain development in children with ASD is atypical as affected children have a larger brain than what is expected of children their age. This effect, however, is not observed after about 6-8 years of age. Other than general and local differences in brain size, the connections between nerve cells in the brain also seems to be different in individuals affected by ASD. 


There have been suggestions that certain childhood vaccines may be associated with ASD. However, no reliable study has been able to show such an association. 

ASD now includes several conditions that were previously considered distinct but now are considered a part of a spectrum. These conditions were autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome. Primary features of ASD involve difficulties in social interaction and communication, repetitive behaviors, and restricted interests. Individuals affected by ASD may have learning and thinking abilities that range from gifted to challenged. Signs and symptoms of ASD typically develop before the age of three and are life-long. Some affected children may develop normally until the age of two but stop developing new skills or experience regression and lose some of the skills they had gained.


Individuals affected by ASD typically experience certain features that affect their ability to communicate or interact in social settings. Language skills vary among affected individuals. Some can speak very well. Some may begin speaking later in childhood, and others may not speak at all or speak very little. Affected children may mistake pronouns. For example, instead of saying “I,” they might say “you.” They may give irrelevant answers when asked a question, may not understand jokes or sarcasm, and may have a flat facial expression. In others, facial expressions may not match what is being said. For example, they might exhibit a sad facial expression when talking about a happy incident. Some affected individuals speak in a robotic voice, avoid eye contact, or have difficulties maintaining a back-and-forth conversation. They may have a hard time understanding the perspective or emotions of others and verbalizing theirs. They may also avoid physical contact.


Another core feature in ASD is repetitive behavior and restricted interests. They may repeat words and phrases over and over or flap their hands, spin in circles, and rock their bodies repeatedly. Affected individuals may be dependent on a strict routine and feel very upset with the slightest changes to their routine. They may pay too much attention to the details of an object such as the wheel of a toy car but not pay attention to the car itself and its overall function. Affected children may play with the same toy the same way every time, line up their toys, and fixate on a certain activity intensely. They may exhibit abnormally intense or indifferent reactions to sounds, smells, tastes, etc. For example, they might have little reaction to pain or a very strong reaction to a loud sound. They can be very organized and feel very upset at small changes.


Other symptoms may include hyperactivity, impulsivity, and difficulty focusing. Unusual eating or sleeping patterns are not uncommon. Some individuals may show aggression, unusual mood, or outbursts. 

ASD can be diagnosed reliably by the age of two but many children do not receive a diagnosis until later on or potentially even adulthood. The first step in diagnosing ASD is developmental screening which routinely done for all children typically at 18 and 24 months of age. As a part of the screening, the physician might speak to the parents and ask a few questions, play with the child or talk to him and observe how the child plays, talks, and interacts with his environment. For children with a higher risk of ASD may require a more detailed screening. Factors that increase the risk of ASD include having older parents, having family members with ASD, and having other genetic conditions associated with ASD. If any problems are identified during the developmental screening, the physician will undertake a comprehensive evaluation. At this step, that child’s parents are interviewed. Depending on the age of the child, teachers may also be interviewed. The physician will then assess the child’s behavior in detail and may also perform genetic testing, as well as tests that assess neurological function, speech, hearing and developmental level. At this step, cognitive, language and age-appropriate skills are evaluated. 

Based on the age of the affected individual, the physician may use scales specifically designed for diagnosing ASD. In addition, genetic testing may be suggested to assess whether other genetic disorders associated with ASD are present such as Rett syndrome and fragile X syndrome. 

There is no cure for ASD and the goal of treatment is to maximize the individual’s ability to communicate, learn, and function by reducing the symptoms related to ASD. There are no medications for ASD specifically, but certain medications can alleviate some of the symptoms such as hyperactivity, impulsivity, and lack of focus.

There are other, non-pharmacological treatment options that help affected individuals. Early interventions from birth to the age of three can significantly help an individual's development and ability to communicate and interact with others.

There are a few different approaches in treating ASD. Behavior and communication approaches target social and verbal skills and behavioral challenges. Applied Behavioral Analysis (ABA) is a common form of treatment that helps the affected child learn new skills that are applicable to social settings and everyday life by encouraging good behaviors and answers and discouraging incorrect behaviors and answers. Discrete Trial Training is a type of ABA where skills are broken down into simple steps and taught. A series of trials are used, where good responses are positively reinforced and incorrect responses are ignored to teach a desirable behavior. Other forms of ABA focus on improving language skills, monitoring self-behavior, learning etc. TEAACH is another form of therapy that teaches skills and behaviors by breaking them down into smaller steps and presenting using visual cues such as flashcards. Sensory integration therapy is a type of therapy that can be helpful if the individual is over- or under-responsive to certain sounds, tastes, sights, or smells.

A different treatment approach involves dietary treatments. Some individuals find vitamin and mineral supplements helpful. However, it is important to consult a physician about the benefits and potential harms of a dietary plan as a treatment option for ASD.

ASD is a life-long condition but the extent of its impact on quality of life varies among affected individuals. Depending on the severity of symptoms low to medium amounts of independence and social inclusion can be expected.

There are autism support groups that can help you find other families affected by this condition can provide you with support and share information and resources. Also, keep a record of conversations and meetings with healthcare professionals or teachers, and copies of doctor evaluations when possible. This information can help you find programs that best suit you or your child’s needs.

Amaral D. Examining the Causes of Autism. Cerebrum. 2017;2017:1-17. Available from


Anagnostou E, Zwaigenbaum L,  Szatmari P, Fombonne E, Fernandez B, Woodbury-Smith M, et al. Autism spectrum disorder: advances in evidence-based practice. Canadian Medical Association Journal. 2014; 186(7): 509-19. DOI:10.1503 /cmaj.121756


Brentani H, Paula C, Bordini D, et al. Autism spectrum disorders: an overview on diagnosis and treatment. Brazilian Journal of Psychiatry. 2013;35 Suppl 1:S62-72. DOI: 10.1590/1516-4446-2013-S104


Center for Disease Control and Prevention. Autism Spectrum Disorder (ASD). Available from


Faras H, Al Ateeqi N, Tidmarsh L. Autism spectrum disorders. Annals of Saudi Medicine. 2010;30(4):295–300. doi:10.4103/0256-4947.65261


Howes O, Rogdaki M, Findon J, et al. Autism spectrum disorder: Consensus guidelines on assessment, treatment and research from the British Association for Psychopharmacology. Journal of Psychopharmacology. 2018;32(1):3–29. doi:10.1177/0269881117741766


Masi A, DeMayo M, Glozier N, Guastella A. An Overview of Autism Spectrum Disorder, Heterogeneity and Treatment Options. Neuroscience Bulletin. 2017;33(2):183–193. doi:10.1007/s12264-017-0100-y


Mayoclinic. Autism Spectrum Disorder. 2018. Available from


National Institute of Mental Health. Autism Spectrum Disorder. Available from,first%20two%20years%20of%20life.


Park H, Lee J, Moon H, et al. A Short Review on the Current Understanding of Autism Spectrum Disorders. Experimental Neurobiology. 2016;25(1):1–13. doi:10.5607/en.2016.25.1.1


Sharma S, Gonda X, Tarazi F. Autism Spectrum Disorder: Classification, diagnosis and therapy. Pharmacology & Therapeutics. 2018;190:91-104. DOI: 10.1016/j.pharmthera.2018.05.007


Yu X, Qiu Z, Zhang D. Recent Research Progress in Autism Spectrum Disorder. Neuroscience Bulletin. 2017;33(2):125–129. doi:10.1007/s12264-017-0117-2







Internet Safety Guide for People with Autism Spectrum Disorders Created by shannon.ashoori
Last updated 1 Jul 2020, 02:01 AM

Posted by shannon.ashoori
1 Jul 2020, 02:01 AM

Hi everyone,

Please refer to the "Disorder Resources" tab for a provided link to an internet safety guide for people with Autism Spectrum Disorders. While the internet is a great way to connect with others and access information, it can also present with a number of risks. This guide provides internet safety guidelines and practical tips to safely navigate the web. Hopefully, you find it helpful.

Low Dose Naltrexone Created by Felicity1980
Last updated 8 Mar 2020, 08:44 AM

Posted by Felicity1980
8 Mar 2020, 08:44 AM

Is anyone here familiar with the research work of Jaak Panskepp and Jaquelyn Mccandles regarding the use of low dose naltrexone for autism?

Community Details Update Created by RareshareTeam
Last updated 30 Oct 2019, 01:54 AM

Posted by RareshareTeam
30 Oct 2019, 01:54 AM

Hi everyone,

The Autism Spectrum Disorder community details have been updated. We added more information about the cause, prevalence, symptoms, diagnosis, and treatment. Hopefully, you find it helpful. 

Communication Created by krislynn200002
Last updated 25 Oct 2008, 12:58 AM

Posted by krislynn200002
25 Oct 2008, 12:58 AM

I have a daughter she is 8 years old today and I"m trying to find out hwo to get her to communicate her needs/wants, we have the boardmaker program and I use the PECS consistanly and also Sign language (ASL). I know that she has many more words in her head just how to get them out? She is also deaf and hard of hearing...Any suggestions would be greatly appreciated.

Welcome Created by biotechguy
Last updated 9 Jul 2008, 04:46 PM

Posted by mummy2three
9 Jul 2008, 04:46 PM

Hi, I am the mother of a verbal high-functioning autistic son. From day 1, I knew that something was wrong with hm but he did not get diagnosed with autism until he was 7-years-old (he is 15 now). His main issues are not sleeping, very compulsive, hyper and major sensory issues.

Posted by biotechguy
7 Jul 2008, 09:33 PM

Welcome to the Autism community!

Community External News Link
Title Date Link
A Helpful Online Safety Guide for People With Autism Spectrum Disorders 07/01/2020
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