[TheMercenary]

Causes
Decades ago, researchers conjectured that infantile autism resulted from rejection of the infant by cold parents ("refrigerator mothers") who were blamed for the occurrence of the social deviations of their young children. Careful family studies have disproved the hypothesis that the development of autistic disorder in children is due to faulty parenting. Communicating repeatedly to the parents of the autistic child that they are not responsible is important. For additional information for parents and people with autism and related conditions, please visit the Autism Society of America.

The causes of autistic disorder are unknown. Hypotheses include obstetric complications, infection, genetics, and toxic exposures.


Obstetric complications are associated with an increased risk of autistic disorder. Whether obstetric complications caused autistic disorder or whether autism and obstetric complications resulted from another problem is unclear.
An infectious basis for autistic disorder in some individuals is suggested by the large number of children with autistic disorder born to women who were infected in the rubella epidemic. This finding supports the hypothesis that this infection triggers a vulnerability to develop autistic disorder in the fetus.
A genetic contribution to the development of autism has been hypothesized.
Multiple family studies have suggested genetic components to many cases of autism. For example, many studies have demonstrated that some asymptomatic first-degree relatives of some probands with autism have abnormalities in serotonin and other chemicals similar to the probands with autism. However, a particular individual with autistic disorder may not exhibit familial traits seen in populations.
Finding genetic bases for autism is a promising research goal. However, the clinical usefulness of the assessment of families of individuals with autism has not been established.
Toxic exposures have been hypothesized to cause autism.
Exposures to toxins, chemicals, poisons, and other substances have been hypothesized to cause autism. Although anecdotal case reports suggest that exposures to toxins and other substances may play a role in isolated cases of autistic disorder, a causative role for toxins in the development of autism in general has not been demonstrated. Local regions may have toxic exposures that exert a geographical influence. For example, the high incidence of autism in portions of Japan has been hypothesized to be due to a toxic effect of fish. Although toxins may play a role in the development of isolated cases of autism in Japan, toxins have not been proved to be causative of autism in Japan in general. Another possible explanation for the high rates of autism in Japan is the excellent training of Japanese clinicians. Low rates of autism in countries outside Japan may reflect the limited abilities of clinicians to make the diagnosis of autism.
In particular, the development of autism after immunization to measles, mumps, and rubella led to the hypothesis that autism was caused by immunization. Careful research has not demonstrated an association between immunization for measles, mumps, and rubella and the subsequent development of autism and related conditions in the general population. General immunization for measles, mumps, and rubella is recommended. Immunization for the general population is highly recommended. The rate of autism in children who receive immunizations does not appear to be increased.