The Missouri Department of Mental Health is notifying 1,000 people that some personal information might have been mailed to an incorrect address.
The department said in a statement Friday that the information released included only the participants' names, not medical or financial information.
The incorrect mailing was caused by a clerical error in printing mailing labels.
The error involved mailing labels on survey questionnaires mailed on Jan. 16. The department says it has corrected the error.
People who are notified by the department may email firstname.lastname@example.org or call toll-free 1-800-207-9329 to address any concerns.