Donna Walker is accused of calling an Indiana couple, and falsely claiming that she might be their daughter, who vanished in 1986 at the age of six.
In setting bail, the judge spoke of Walker's past mental health problems, and said he considered her a flight risk.
He also said that if she were to make bond, she wouldn't be able to leave the Topeka area, and wouldn't have access to telephones.
Authorities allege that Walker called the parents of Shannon Marie Sherrill and said she might be their daughter. Investigators grew suspicious when the caller refused to give her phone number.
Indiana authorities are seeking her extradition.