Parents of children with autism were roughly twice as likely to have been hospitalized for a mental disorder than parents of children without autism, according to a new study from U.S. and European researchers.

The study, an analysis of Swedish birth and hospital records, appears in the May 5 issue of the Official Journal of the American Academy of Pediatrics.

Researchers examined 1,237 children born between 1977 and 2003 who were diagnosed with autism before age 10, and compared them with 30,925 control subjects who matched by gender, year of birth and hospital.

“We are trying to determine whether autism is more common among families with other psychiatric disorders," said study author Julie Daniels in a news release. Daniels is an assistant professor at the University of North Carolina at Chapel Hill School of Public Health. "Establishing an association between autism and other psychiatric disorders might enable future investigators to better focus on genetic and environmental factors that might be shared among these disorders."

Daniels said earlier studies had shown a higher rate of psychiatric disorders in families of autistic children than in the general population.

The new study found that mothers and fathers diagnosed with schizophrenia were about twice as likely to have a child diagnosed with autism.

"We also saw higher rates of depression and personality disorders among mothers, but not fathers,” Daniels said.

Autism is a developmental disorder defined by impaired social interaction, communication and behavior that results in restricted and repetitive behavior. The causes of autism are still widely unknown although research has linked it to genetics. In very rare cases, autism has been associated with birth defects (teratology).

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