Since 1973, Chestnut Health Systems has been providing behavioral health care in Illinois. Chestnut Health Systems offers an array of services, including chemical dependency treatment for adults and adolescents; counseling and mental health services; services for the chronic mentally ill; employee assistance programs; credit counseling; problem gambling services; workplace and behavioral health care management programs; and early intervention and prevention programming, as well as a research, training and publications component called Lighthouse Institute. Chestnut operates multiple chemical dependency and mental health treatment centers in central and southern Illinois. The company is accredited by the Joint Commission on Accreditation of Healthcare Organizations. Chestnut Health Systems employs approximately 600 people and is headquartered in Bloomington, Ill., and has a location in Granite City, Ill.