U.S. researchers call off controversial autism study

CHICAGO -- A government agency has dropped plans to test a controversial treatment for autism that critics had called an unethical experiment on children.

The National Institute of Mental Health said in a statement Wednesday that the study of chelation (kee-LAY'-shun) has been discontinued. The statement says the agency decided the money would be better used testing other potential therapies for autism and related disorders.

The study had been on hold because of safety concerns. A study published last year linked a chemical used in the treatment to lasting brain problems in rats.

The treatment removes heavy metals from the body and is based on the fringe theory that mercury in vaccines triggers autism -- a theory never proved and rejected by mainstream science.