A multi-million-dollar federal grant will allow Mercer County Behavioral Health Commission to continue treating people with mental illness and substance-abuse problems.

Mercer County will have a share in federal grants totaling $3.9 million, the state announced Tuesday. Mercer is one of five counties that will be able to tap into the money to enhance their adult treatment programs.

The five-year grants are doled out by the Substance Abuse and Mental Health Services Administration, a federal agency.

The money will go toward a pilot program called MISA -- short for Mental Illness and Substance Abuse service -- to treat people diagnosed with both problems, said Joe Montone of Behavior Health.