A comprehensive study of Swedish medical records has turned out an interesting conclusion which may help shed some light on autism. It appears that children diagnosed with the mental disorder have double the chances of having parents who have a history of mental illness.

"The study suggests there is no evidence of specific transmission of specific psychiatric disorders -- i.e. schizophrenia, depression and personality disorders -- across generations, but that there is more a complex genetic diathesis, a genetic vulnerability, which increases the risk for autism and perhaps other psychiatric illness," said Dr. Jon Shaw, director of child and adolescent psychiatry at the University of Miami Miller School of Medicine, to The Washington Post.

It is still unclear what is the cause for autism, but a combined cause with a large genetic component is suspected. Currently, there is still much debate whether autism is caused by mutations or by an interaction of an array of genes. There is evidence to sustain both causes. While this study points out that multigene interaction may be the culprit for the incurable disorder, it is also known that teratogens also are associated with autism.

People affected by the disorder are characterized by social impairments and often lack the intuition about others that many people take for granted. Autism Spectrum Disorders are associated with periods of severe tantrums and one third of autistic children also have displayed aggression, especially when the disorder is associated with mental retardation (as it often, but not always, happens).