The Myths About Autism

Approximately 1 in 88 children suffer from an autism spectrum disorder (ASD), according to estimates from the Centers for Disease Control and Prevention (CDC'). The disorder occurs among all racial, ethnic, and socioeconomic groups. 

As in most conditions, researchers believe that ASD is due to a combination of environmental and genetic factors. Because the causes are not clearly defined, a number of myths circulate regarding the disorder.

Myths

The following are a few myths about ASD. A more detailed list, prepared by scientists at Johns Hopkins University is available here:

Myth: Induced labor increased the risk of ASD:

Fact: According to a new Committee Opinion released by The American College of Obstetricians and Gynecologists (ACOG) on April 2014, there is no connection between induced labor and ASD. Some studies have suggested an association between ASD and the use of oxytocin for labor induction or stimulation; however, available evidence is inconsistent and does not demonstrate causation. The ACOG opinion also found significant limitations in study design and conflicting findings in existing research.

Myth: The World Health Organization (WHO) reported that a 1998 study raised concerns about a possible link between measles-mumps-rubella (MMR) vaccine and ASD; however, the study was later found to be seriously flawed, and the paper has been retracted by the journal that published it. Unfortunately, its publication sparked a panic that led to decrease in immunization rates, and subsequent outbreaks of these diseases. There is no evidence of a link between MMR vaccine and ASD.

Myth: ASD is a behavioral/emotional/mental health disorder.

Fact: According to Johns Hopkins University, ASD comprises developmental disabilities and neuro-biological disorders. These disorders surface in early childhood (usually before the age of three or four) and are likely to last the lifetime of the person.

Suggested causes of ASD

Although genetic factors are most likely involved, a number of studies have pointed to environmental factors. They include:

Air pollution: A study by researchers at Harvard Medical School published on December 18, 2014 compared 245 children with ASD to 1,522 children without the disorder. The investigators found that maternal exposure to air pollution during pregnancy, particularly during the third trimester (last three months of pregnancy), was related to a greater risk of their offspring having ASD. Another study by researchers at the University of Rochester School of Medicine exposed newborn mice to a form of air pollution known as ambient ultrafine particles (CAPS). The exposure produced brain abnormalities that were similar to ASD or schizophrenia.

Pesticides: A study published on June 23 by researchers at the University of California, Davis and UCLA reported that women exposed to pesticides during pregnancy are more likely to deliver a child with ASD and other neurodevelopmental disorders. The researchers compared the risk of ASD between those delivered by mothers who resided near an agricultural area that used pesticides to those that did not. The authors concluded that their study strengthens the evidence that links neurodevelopmental disorders to pesticide exposure during pregnancy; moreover, organophosphates, including pyrethroids and carbamates, are particularly harmful.

Maternal antidepressant use: A study published on April 14, 2014 by researchers at Johns Hopkins University, the University of Massachusetts Medical School, and the University of California, Davis reported that the offspring of women who take antidepressants during pregnancy are more likely to suffer from ASD or developmental delay. The researchers conducted a study on the use of commonly-prescribed antidepressants, known as selective serotonin reuptake inhibitors (SSRIs) during pregnancy and the risk of ASD and other developmental delays in their offspring. 

SSRIs include Prozac, Paxil, Lexapro, and Zoloft. The study group comprised 966 mother-child pairs (492 with ASD, 154 with developmental delays, and 320 with normal development. The investigators found that prenatal SSRI exposure was almost three times as likely to be present in children with ASD, compared to normal children. In addition, the strongest association was found with first-trimester (first three months of pregnancy) exposure. Exposure was also found to be higher among boys with developmental delay and was strongest in the third trimester.

Industrial chemicals: study published in the March 2014 edition of the journal Lancet Neurology noted that the number of industrial chemicals known to be related to ASD has more than doubled over the past seven years. In 2006, they conducted a literature review and identified five industrial chemicals as developmental neurotoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. They note that, since 2006, studies have identified six additional toxins that cause neurodevelopmental disabilities: manganese, fluoride, chlorpyrifos, dichlorodiphenyltrichloroethane (DDT), tetrachloroethylene, and the polybrominated diphenyl ethers.

Prevention

Based on the evidence above, avoidance of maternal exposure to pesticides, air pollution, antidepressants, and industrial chemicals can reduce the risk of ASD in offspring. Also, healthy lifestyle choices such as a healthy diet, avoidance of drugs, and avoidance of tobacco can benefit both the health of a mother and her unborn child. For example, a study published on June 27, 2013 in the American Journal of Epidemiology reported that consumption of omega-3 and omega-6 fatty acids during pregnancy may reduce the risk of ASD in their offspring.