What Causes Autism?

The information below is not meant to diagnose or treat. It should not take the place of consultation with a qualified healthcare professional.

A common question after an autism diagnosis is what is the cause of autism.

We know that there’s no one cause of autism. Research suggests that autism develops from a combination of genetic and nongenetic, or environmental, influences.

These influences appear to increase the risk that a child will develop autism. However, it’s important to keep in mind that increased risk is not the same as cause. For example, some gene changes associated with autism can also be found in people who don’t have the disorder. Similarly, not everyone exposed to an environmental risk factor for autism will develop the disorder. In fact, most will not.

Autism’s genetic risk factors

Research tells us that autism tends to run in families. Changes in certain genes increase the risk that a child will develop autism. If a parent carries one or more of these gene changes, they may get passed to a child (even if the parent does not have autism). Other times, these genetic changes arise spontaneously in an early embryo or the sperm and/or egg that combine to create the embryo. Again, the majority of these gene changes do not cause autism by themselves. They simply increase risk for the disorder.Some Psychotropic medications such as Depakote Thorazine, Melaril and others may cause defects to new born children.
See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000213/

NIH- National Library of Medicine

Valproate is used for the treatment of epilepsy and other neuropsychological disorders and may be the only treatment option for women of childbearing potential. However, prenatal exposure to valproate may increase the risk of autism.
Prenatal Valproate Exposure and Risk of Autism Spectrum Disorders and Childhood Autism
SEE : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511955/

Autism’s environmental risk factors

Research also shows that certain environmental influences may further increase – or reduce – autism risk in people who are genetically predisposed to the disorder. Importantly, the increase or decrease in risk appears to be small for any one of these risk factors:

Increased risk

• Advanced parent age (either parent)
• Pregnancy and birth complications (e.g. extreme prematurity [before 26 weeks], low birth weight, multiple pregnancies [twin, triplet, etc.])
• Pregnancies spaced less than one year apart

Decreased risk

• Prenatal vitamins containing folic acid, before and at conception and through pregnancy

No effect on risk

Vaccines. Each family has a unique experience with an autism diagnosis, and for some it corresponds with the timing of their child’s vaccinations. At the same time, scientists have conducted extensive research over the last two decades to determine whether there is any link between childhood vaccinations and autism. The results of this research is clear: Vaccines do not cause autism. The American Academy of Pediatrics has compiled a comprehensive list of this research.

Differences in brain biology

How do these genetic and nongenetic influences give rise to autism? Most appear to affect crucial aspects of early brain development. Some appear to affect how brain nerve cells, or neurons, communicate with each other. Others appear to affect how entire regions of the brain communicate with each other. Research continues to explore these differences with an eye to developing treatments and supports that can improve quality of life.

Autism Statistics and Facts

Autism Prevalence

• In 2021, the CDC reported that approximately 1 in 44 children in the U.S. is diagnosed with an autism spectrum disorder (ASD), according to 2018 data.
  • 1 in 27 boys identified with autism
  • 1 in 116 girls identified with autism
• Boys are four times more likely to be diagnosed with autism than girls.
• Most children were still being diagnosed after age 4, though autism can be reliably diagnosed as early as age 2.
• 31% of children with ASD have an intellectual disability (intelligence quotient [IQ] <70), 25% are in the borderline range (IQ 71–85), and 44% have IQ scores in the average to above average range (i.e., IQ >85).
• Autism affects all ethnic and socioeconomic groups.
• Minority groups tend to be diagnosed later and less often.
• Early intervention affords the best opportunity to support healthy development and deliver benefits across the lifespan.
• There is no medical detection for autism.

What causes autism?

• • Research indicates that genetics are involved in the vast majority of cases.
  • Children born to older parents are at a higher risk for having autism.
  • Parents who have a child with ASD have a 2 to 18 percent chance of having a second child who is also affected.
  • Studies have shown that among identical twins, if one child has autism, the other will be affected about 36 to 95 percent of the time. In non-identical twins, if one child has autism, then the other is affected about 31 percent of the time.
  • Over the last two decades, extensive research has asked whether there is any link between childhood vaccinations and autism. The results of this research are clear: Vaccines do not cause autism.

Intervention and Supports

• • Early intervention can improve learning, communication and social skills, as well as underlying brain development.
  • Applied behavior analysis (ABA) and therapies based on its principles are the most researched and commonly used behavioral interventions for autism.
  • Many children affected by autism also benefit from other interventions such as speech and occupational therapy.
  • Developmental regression, or loss of skills, such as language and social interests, affects around 1 in 5 children who will go on to be diagnosed with autism and typically occurs between ages 1 and 3.

Associated Challenges

• An estimated 40 percent of people with autism are nonverbal.
• 31% of children with ASD have an intellectual disability (intelligence quotient [IQ] <70) with significant challenges in daily function, 25% are in the borderline range (IQ 71–85).
• Nearly half of those with autism wander or bolt from safety.
• Nearly two-thirds of children with autism between the ages of 6 and 15 have been bullied.
• Nearly 28 percent of 8-year-olds with ASD have self-injurious behaviors. Head banging, arm biting and skin scratching are among the most common.
• Drowning remains a leading cause of death for children with autism and accounts for approximately 90 percent of deaths associated with wandering or bolting by those age 14 and younger.

Associated Medical & Mental Health Conditions

• Autism can affect the whole body.
• Attention Deficient Hyperactivity Disorder (ADHD) affects an estimated 30 to 61 percent of children with autism.
• More than half of children with autism have one or more chronic sleep problems.
• Anxiety disorders affect an estimated 11 to 40 percent of children and teens on the autism spectrum.
• Depression affects an estimated 7% of children and 26% of adults with autism.
• Children with autism are nearly eight times more likely to suffer from one or more chronic gastrointestinal disorders than are other children.
• As many as one-third of people with autism have epilepsy (seizure disorder).
• Studies suggest that schizophrenia affects between 4 and 35 percent of adults with autism. By contrast, schizophrenia affects an estimated 1.1 percent of the general population.
• Autism-associated health problems extend across the life span – from young children to senior citizens. Nearly a third (32 percent) of 2 to 5 year olds with autism are overweight and 16 percent are obese. By contrast, less than a quarter (23 percent) of 2 to 5 year olds in the general population are overweight and only 10 percent are medically obese.
• Risperidone and aripiprazole, the only FDA-approved medications for autism-associated agitation and irritability.

Caregivers & Families

• • On average, autism costs an estimated $60,000 a year through childhood, with the bulk of the costs in special services and lost wages related to increased demands on one or both parents. Costs increase with the occurrence of intellectual disability.
  • Mothers of children with ASD, who tend to serve as the child’s case manager and advocate, are less likely to work outside the home. On average, they work fewer hours per week and earn 56 percent less than mothers of children with no health limitations and 35 percent less than mothers of children with other disabilities or disorders.

Autism In Adulthood

• • Over the next decade, an estimated 707,000 to 1,116,000 teens (70,700 to 111,600 each year) will enter adulthood and age out of school based autism services.
  • Teens with autism receive healthcare transition services half as often as those with other special healthcare needs. Young people whose autism is coupled with associated medical problems are even less likely to receive transition support.
  • Many young adults with autism do not receive any healthcare for years after they stop seeing a pediatrician.
  • More than half of young adults with autism remain unemployed and unenrolled in higher education in the two years after high school. This is a lower rate than that of young adults in other disability categories, including learning disabilities, intellectual disability or speech-language impairment.
  • Of the nearly 18,000 people with autism who used state-funded vocational rehabilitation programs in 2014, only 60 percent left the program with a job. Of these, 80 percent worked part-time at a median weekly rate of $160, putting them well below the poverty level.
  • Nearly half of 25-year-olds with autism have never held a paying job.
  • Research demonstrates that job activities that encourage independence reduce autism symptoms and increase daily living skills.

Economic Costs

• The cost of caring for Americans with autism had reached $268 billion in 2015 and would rise to $461 billion by 2025 in the absence of more-effective interventions and support across the life span.
• The majority of autism’s costs in the U.S. are for adult services – an estimated $175 to $196 billion a year, compared to $61 to $66 billion a year for children.
• On average, medical expenditures for children and adolescents with ASD were 4.1 to 6.2 times greater than for those without autism.
• Passage of the 2014 Achieving a Better Life Experience (ABLE) Act allows tax-preferred savings accounts for people with disabilities, including autism, to be established by states.
• Passage of autism insurance legislation in all 50 states is providing access to medical treatment and therapies.

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