Mental Health and Substance use Disorder Parity

Left untreated, mental health and substance use disorders can be debilitating and life-threatening. Parity laws are federal and state regulations that remove limits imposed by health insurers on access to mental health benefits that are more restrictive than those imposed on medical and surgical benefits.

In 1996, the Mental Health Parity Act of 1996 required that large group health plans could not impose annual or lifetime dollar limits on mental health benefits that were less favorable than the limits imposed on medical and surgical benefits. Since then, more federal laws related to mental health parity have been passed.

In 2008, for example, the Mental Health Parity and Addiction Equity Act (MHPAEA) was enacted to ensure that large group health plans treat mental health and substance use disorders (MH/SUD) similarly to how they treat other health conditions.

In 2010, the Affordable Care Act (ACA) amended the MHPAEA to extend this requirement of parity to individual and small group health plans. The ACA also generally requires all individual and small group health plans, including plans offered through the ACA Marketplace, to cover mental health and substance use disorder services as an essential health benefit. However, certain grandfathered plans were not required to offer the rights and protections of ACA Marketplace plans. 

In 2015, Illinois enacted a new law to advance parity implementation and expand on the Federal law. The new law included important provisions to extend and clarify coverage, educate consumers about their rights, require certain minimum treatment benefits, and improve enforcement of the law.

Since 2019, Illinois law has required all grandfathered plans to cover mental health and substance use disorder services. Illinois law subjects grandfathered plans and non-grandfathered plans to all the same requirements for parity in coverage of MH/SUD and medical or surgical services.


In Illinois, every insurer that offers individual or group health insurance coverage is required to provide coverage based on medical necessity for the treatment of a mental, emotional, nervous, or substance use disorder or condition.

Your coverage must not impose financial requirements (i.e., deductibles, copayments, coinsurance, out-of-pocket maximums) or treatment limitations (e.g., number of visits, waiting periods, network restrictions, step-therapy requirements, and more) on MH/SUD benefits that are more restrictive than the predominant financial requirements and treatment limitations that the coverage applies to substantially all hospital and medical benefits. There must not be separate financial requirements or treatment limitations that apply only to MH/SUD benefits. The coverage must be no less favorable for MH/SUD benefits than for hospital and medical benefits in terms of annual or lifetime dollar limits.

Please be aware that self-funded plans of individual private employers are not subject to Illinois requirements, though they are subject to the federal MH/SUD requirements and to the federal exemption for grandfathered plans. If you have coverage through an employer and are not sure whether it is self-funded or grandfathered, check with your plan's benefits administrator. You can also visit: for more information about grandfathered plans.

Neither Illinois nor federal MH/SUD coverage and parity requirements apply to short-term, limited-duration health insurance coverage or to excepted benefit policies, such as specified disease policies, Medicare supplement insurance, long-term care insurance, dental-only policies, and certain other policies with limited benefits that are not designed to stand alone as minimum essential coverage.


Recommendations to help navigate your health coverage, as it relates to mental health and substance use disorder treatments:

  • Learn the laws that protect you when you are seeking mental health and substance use disorder treatment.
  • Contact your health insurer for assistance. Find out which doctors are in-network.
  • Understand your health insurance plan and what types of care will need pre-authorization.
  • Know your rights to request an internal appeal and then an external review for denials, reduction in reimbursement, or failure of your insurance company to make a payment.

For questions related to mental health and substance use disorder parity laws, or to talk to someone about concerns related to your plan's compliance, contact the Office of Consumer Health Insurance at 877-527-9431.

For more information about ACA Health Insurance Marketplace plans, visit:



Medicare, Medicaid and the Children's Health Insurance Program (CHIP), also known as All Kids, are public health plans through which individuals obtain health coverage. The programs are separate from Get Covered Illinois and the Illinois Department of Insurance.

For more information about Medicare, contact Centers for Medicare and Medicaid Services, visit:

For more about Medicaid and the Children's Health Insurance Program (CHIP) / All Kids, visit: or call 800-843-6154.