Curriculum · Mental Health / Psychiatry
Autism spectrum disorder
What it is
Autism is a pervasive developmental disorder. According to the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision, a patient must exhibit impairments in all of the following: 1) qualitative impairment in social interaction; 2) qualitative impairment in communication; 3) restricted, repetitive, and stereotyped patterns of behavior. In the regressive form, children show relatively normal development from 12 to 24 months of age but subsequently lose the skills they have previously obtained.
Causes and risk
Autism affects boys about four times more frequently than girls and occurs in approximately 6 per 10,000 people. Genetic factors seem to be contributory: autism is seen more frequently in identical twins than fraternal twins. The prevalence is put elsewhere at 3-6 per 1000 live births. The condition is not the result of emotional trauma or deviant parenting, and there is no evidence for a suggested link with the MMR vaccine; it may arise as the result of different organic processes, in many cases no specific cause can be identified, and there is probably multiple aetiology with a genetic component in at least some. Vaccines are not among the causes, and the question is put in the clinic outright. Where parents are considering not immunizing their child because a relative had autism spectrum disorder diagnosed 2 months after receiving a vaccine, the appropriate response is to inform them that the evidence does not support a link between vaccines and autism - not to ask them to sign a vaccine refusal form, not to delay immunizations until 18 months, and not to tell them their child can no longer be cared for if unimmunized.