Written by: Dr Pierrette Mimi Poinsett MD
Reviewed by: Dr. RY Langham PhD
Table of Contents
- Types of ASD
- Prevalence (Statistics)
- Warning Signs
- Risk Factors
Autism spectrum disorder (ASD) is a group of neuro-developmental disorders.
The “neuro” part refers to the brain, the “developmental” part refers to behavior, and the “spectrum” part refers to the variation in severity and symptoms.
Autism symptoms vary from person-to-person, but symptoms may include communication and social interactions problems and behavioral issues. 
Types of ASD
In the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) there are no longer different types of ASD: Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder are all classified as ASD and are not treated as separate disorders. 
One out of 68 boys and girls will develop some form of autism spectrum disorder. However, ASD is 3-to-5 times more prevalent in boys than in girls.
Image source: National Institute of Mental Health
The warning signs vary from person-to-person; however, there are some common early and late indicators of ASD.
Early and late indicators of ASD are listed below:
Early indicators in children
- No babbling or pointing by age 1
- No single words by age 16-months or two-word phrases by age 2
- No response to his/her name
- Loss of language or previously acquired social skills
- Poor or no eye contact
- Excessive lining up or organizing of toys or objects
- No smiling or social responsiveness
Late indicators in children
- An inability to make or keep friends
- An inability to initiate and/or sustain conversations
- Absent or impaired imaginative and social play
- A repetitive or unusual use of language
- An intense, focused interest in one thing
- A preoccupation with certain objects or subjects
- An inflexible adherence to preset routines or rituals
Although ASD symptoms can vary, some symptoms are common in children and adults with the condition. 
Common ASD symptoms are listed below:
- Problems using or understanding language
- An inability to switch from topic-to-topic in conversations
- Repeating words or phrases
- Limited speech
Difficulty Relating to People, Events, and Things
- Problems developing and retaining friendships
- Poor eye contact
- Difficulty reading facial expressions
Repetitive Body Movements or Behaviors
- Repeating sounds or phrases
It is important to note that although autism spectrum disorder affects children of all races and ethnicities, some individuals are more at-risk for developing the condition than others. 
Listed below are the possible risk factors for ASD:
- Gender: Boys are 3-to-5 times more likely to develop ASD, than girls.
- Extreme Prematurity: Babies born before 26 weeks’ gestation have a greater risk of developing ASD later in life.
- Family History: Families with at least one child with ASD have an increased risk of having another child with the disorder.
- Genetic Disorders: Children with certain genetic disorders have a higher risk of developing ASD or “autism-like” symptoms, than those without them. For example, a child with Fragile X syndrome, tuberculosis, or Rett syndrome will have an increased risk of also developing ASD.
- Parental Age: Children, who are born to older parents, have a higher risk of developing ASD, than those born to younger ones.
The cause of ASD also varies, but environmental and genetic factors appear to play a significant role in the development of this disorder. [3, 4]
Some children with ASD experience changes in parts of their brains. In fact, some researchers suggest that ASD is the result of “interferences” in the brain during early development. In other words, the genes that control brain development become defective, leading to the emergence of ASD.
Other researchers believe that environmental factors (i.e. viruses, pollution, etc.) trigger ASD.
ASD is not due to parenting or the so-called “refrigerator mother” phenomenon.
Multiple studies have found that ASD is also not due to vaccines like the MMR vaccine. Previous studies that suggested a link between vaccines and autism have been retracted, due to poor study design and questionable research methods.
There has been an increase in the development ASD in children, but this may be due to increased and more accurate diagnosing.
In order for a child to receive the best treatment outcome and quality of life, it is imperative that he/she be diagnosed with the condition, as early as possible. The American Academy of Pediatrics recommends that children be screened for ASD during their 18-month and 24-month well-child visits.
Most pediatricians use the Modified Checklist for Autism in Toddlers (M-CHAT): a 23-point questionnaire that identifies the risk of autism. Depending on the score, it can lead a pediatrician to further investigate language delays, behavioral issues, and/or the need for additional genetic, neurologic, or developmental testing. 
Other developmental screening tools include:
- Ages and Stages Questionnaires (ASQ)
- Communication and Symbolic Behavior Scale (CSBS)
- Parents’ Evaluation of Developmental Status (PEDS)
- Screening Tool for Autism in Toddlers and Young Children (STAT). 
It is important to note that at this time there are no “foolproof” screening tools for ASD.
Most of the current screening tests only help health professionals determine if they should follow-up with additional testing.
Comprehensive diagnostic testing is often performed by a multidisciplinary team including developmental pediatricians, neurologists, child psychologists or psychiatrists, speech and language professionals, and/or other developmental specialists.
This testing should also include a hearing testing because children with hearing problems and delayed speech may be mistakenly diagnosed with ASD, even if they do not have it. 
Note: Children under the age of three are often referred to early intervention programs, while children over the age of three are usually referred to school-based special education services.
Listed below are common tests specifically used to diagnose ASD: 
- Autism Diagnosis Interview: Revised (ADI-R)
- Autism Diagnostic Observation Schedule-Generic (ADOS-G)
- Childhood Autism Rating Scale
- Gilliam Autism Rating Scale-Second Edition (GARS-2)
Like diagnostic tests, there is no specific medical test that can diagnose ASD. Medical tests are only used to identify symptoms, commonly associated with the disorder. 
The cytogenetic microarray test, a type of genetic test, is often used to assess ASD. It can detect chromosomal abnormalities linked to the disorder, which is beneficial because 15% of children with ASD have these chromosomal abnormalities. Genetic testing is recommended if a child, suspected of having ASD has uncommon physical features and/or if there is a history of fragile X syndrome, intellectual disability, or any other genetic disorder (such as tuberculous or Rett syndrome) in the family.
A child suspected of having ASD may also be tested for lead. High levels of lead can lead to developmental impairments that mimic ASD symptoms. Lead testing is often used to rule-in or rule-out ASD.
If previous test results are inconclusive, a doctor may order additional tests to help diagnose ASD.
Between 10% and 20% of children with ASD have seizure disorders, so brain imaging tests such as Electroencephalogram (EEG), and Magnetic Resonance Imaging (MRI) may be used.
Vitamin and mineral tests may also be ordered if a child is an extremely picky eater.
Medical Tests Not Recommended
The following tests do not yield beneficial results in the treatment of ASD, therefore, they should not be ordered by a doctor: 
- Hair Analysis
- Intestinal Permeability Studies
- Measurement of Mercury or Other Heavy Metals
- Stool Analysis
- Urinary Peptides Analysis
There is a wide-variety of ASD treatments available that can improve your child’s life.
These treatments are listed below: 
Educational/behavioral interventions can help children and their families cope with the ASD symptoms. These highly structured resources can also improve a child’s communication, behavior, and problem-solving skills. For instance, a behavioral analysis focuses on positive behaviors, while minimizing the negative ones.
Family therapy, on the other hand, helps families cope better with the stress of having a child with ASD.
Children with ASD may also need special education services to help them perform to the best of their abilities inside the classroom.
There is wide-range of medical treatments that can help people with ASD.
Medical treatments are designed to treat (not cure) the symptoms of ASD. It is common for children with ASD to experience anxiety, depression, and obsessive-compulsive disorder (OCD) tendencies – emotional distress that needs medical treatment.
In addition, antipsychotic medications are sometimes used to treat severe behavioral problems.
According to current research, approximately 15% of children with ASD have seizure disorders that require anticonvulsant treatment.
Some children with ASD are highly hyperactive and impulsive, so there are also medications that can help with these symptoms.
Medical Treatments Not Recommended
Some medical treatments have not been proven successful in the treatment of ASD, for either children or adults. For instance, medical treatments like: chelation, bleach enemas, specialized diets do not appear to aid in the treatment of this condition. In fact, some researchers believe that these treatments are possibly harmful to those with the ASD.
There is no cure for ASD. 
However, with early intervention and continuous behavioral therapies, a child’s communication and social interaction can improve.
Therefore, the outlook for a person with ASD varies greatly, and is highly dependent on factors like initial symptom presentation, early interventions, and individual symptoms.
In other words, one person with ASD may present with a severe language impairment that needs support for daily functioning and activities, while another may only have a mild communication delay that only needs minimal support for daily functioning and activities.
That is where the “spectrum” part of ASD comes into the equation.
For more information on autism (i.e. definition, symptoms, diagnosis, treatment, and/or outlook), check out the following resources:
Autistic Self Advocacy Network: https://www.autisticadvocay.org
Mental Health and Autism Insurance Project: https://www.mhautism.org/
Thinking Person’s Guide to Autism: https://www.thinkingautismguide.com
Neurotribes: The Legacy of Autism and the Future of Neurodiversity (by Steve Silberman)
American Psychiatric Association (APA). (2016). What is autism spectrum disorder? Retrieved from https://www.psychiatry.org/patients-families/autism/what-is-autism-spectrum-disorder
National Institute of Neurological Disorders and Strokes (NIH). (2017). Autism spectrum disorder: Fact Sheet. Retrieved from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Autism-Spectrum-Disorder-Fact-Sheet#3082_1
Mayo Clinic. (2018). Autism spectrum disorder. Retrieved from https://www.mayoclinic.org/diseases-conditions/autism-spectrum-disorder/symptoms-causes/syc-20352928
Healthy Children. (2016). Doctors screen for autism. Retrieved from https://www.healthychildren.org/English/health-issues/conditions/Autism/Pages/How-Doctors-Screen-for-Autism.aspx
Centers of Disease Control and Prevention. (2016). Autism spectrum disorder, screening and diagnosis for health care providers. Retrieved from https://www.cdc.gov/ncbddd/autism/hcp-screening.html
Healthy Children. (2-16). If autism is suspected – What’s next? Retrieved fromhttps://www.healthychildren.org/English/health-issues/conditions/Autism/Pages/If-Autism-is-Suspected-Whats-Next.aspx