Does Anyone Really Know What Causes Autism?

Autism is a common disorder that affects children in many different ways – some have common types, some have rare types, some experience additional ADD, ADHD, or anxiety symptoms – yet the causes of autism are still unknown. Recent research on this complicated disorder points to genetics or heredity, neurological factors, and environmental factors all playing a role in the development of autistic spectrum disorder.

What is Autistic Spectrum Disorder?

To be brief, autistic spectrum disorder (which is what many people are referring to when they use the term ‘autism’ is a developmental disorder characterized by social impairments, difficulty communicating, and repetitive patterns of behavior. Autistic spectrum disorder is broken into 5 different subtypes; the common Asperger’s, autistic disorder, and pervasive developmental disorder – not otherwise specified, as well as the rarer Rett syndrome and childhood disintegrative disorder. Each subtype has its own characteristic signs and symptoms.

What are the Causes of autistic spectrum disorder?

This is where things get fuzzy. Though there has been a lot of speculation in recent years, not enough research has been done to point to one specific factor that causes this disorder. Even so, here is a brief rundown of the many factors that are thought to cause autism in one way or another:

Genetic / Hereditary Factors:

Families that have one child with autism have a 1 in 20 chance of having another child with autism. In twins, if one has the disorder there is a 60% chance that the other has it as well.
Besides this, research has shown that genetic changes that result in autism may arise spontaneously. Approximately 20 genes have been identified that are thought to have a part in causing autism. While these genes are located all over, they all have one thing in common: they all play a role in brain growth, brain development, and the communication of cells within the brain.

Fragile X Syndrome

One of the most common known causes of autism is fragile X syndrome, which is a genetic disorder that causes behavioral and learning challenges, intellectual disabilities, and unusual physical characteristics. It affects males more than females, though approximately one-third of males with this syndrome display autistic symptoms. Though fragile X syndrome is not the cause of all cases of autism, you should have a doctor rule out the possibility of your child having fragile X syndrome before considering other causes.

Neurological Factors:

There are particular areas of the brain that are thought to play a role in the symptoms of autism.
Two of these – the cerebellum and the cerebral cortex – are responsible for movement, mood regulation, and concentration. If these two areas do not develop properly, autistic symptoms may begin to appear.

Irregular levels of neurotransmitters – in particular serotonin and dopamine – have also been linked to autism. A lack or excess of dopamine can cause problems with movement and concentration, while irregular serotonin levels can have negative effects on mood.

Environmental Factors:

• It is believed that certain childhood vaccines may trigger autism in certain children. Those who have been genetically predisposed to autoimmune, immune, or inflammatory conditions are particularly at risk.

• Chemicals in certain pesticides may also trigger autism in those who are already genetically predisposed.

• A study conducted by UC Davis Health System researchers found that women who have children at 40 years or older have a 50% greater risk of having an autistic child than women who are in their 20s.

• Another study found that women who did not take prenatal vitamins were twice as likely to birth an autistic child.

• Children who are exposed to certain medications in the womb, such as SSRIs (antidepressants), valproic acid (an anticonvulsant), and thalidomide (treatment for a skin disease) have a higher risk of developing autism.

• Children born to women who have been living within 1000 feet of a major highway are twice as likely to develop autism. The air pollution due to high levels of traffic can lead to memory problems and brain damage.

• Lead: Lead has been shown to cause brain damage in developing children, causing many learning and health problems. Avoid direct contact with old paint, and eat a diet high in calcium and iron including dairy and leafy greens; these foods can help block your body from harmful lead exposure.

• Mercury: High levels of mercury have been proven to be toxic to developing fetuses. To avoid mercury, don’t eat large amounts of fatty fish.

Causes of Autism

The unfortunate reality is that no one has come up with the one particular factor that causes autism. Since most cases of autism are unique from each other, it’s difficult to pinpoint exactly where the disorder comes from. While many studies point to genetics, many more point to environmental factors. Some even stress that it is a combination of both. It may be caused by certain medications and infections the child was exposed to in the womb, or it may be the result of spontaneous genetic mutations.

The autistic spectrum is just that – a spectrum; with many symptoms and ways of affecting children, it may be that each subtype is caused by a completely different factor. Until more research is completed, the exact answer to this question is unknown. Unfortunately, the causes of autism and other developmental and behavioral disorders such as ADHD and ADD remain a mystery for now.