Chestnut Health Systems

Chestnut Health Systems is a U.S. nonprofit healthcare organization focused on integrated behavioral health, substance use treatment, primary care, dental services, supportive housing, and applied research. The organization operates across Illinois and Missouri and provides residential and outpatient addiction treatment, mental health services, prevention and recovery support, and community-based care. Chestnut also houses Lighthouse Institute, a research arm focused on behavioral health research, implementation science, training, and publications. Rather than functioning as a drug-development biotech, Chestnut is a service-delivery and research organization with established commercial healthcare operations and longstanding accreditation.