The federal Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act (MHPAEA) may be the 700-pound gorilla of health system change laws.

The 800-pound gorilla — the Patient Protection and Affordable Care Act of 2010 (PPACA) — has been crowding out news about the how the MHPAEA is affecting health plan coverage for mental health care and substance abuse treatment services.

Michael Leyburn Halford and Stephen Melek, speakers from Milliman Inc., Seattle, gave an MHPAEA update presentation in Boston, at the Society of Actuaries’ SOA2011 Health Meeting.

Like an earlier 1996 federal mental health parity law, the MHPAEA, which was enacted in 2008, affects only employers that choose to offer behavioral benefits, and requires those employers to offer parity between the benefits rules for the behavioral conditions they choose to cover and the benefits rules for “subtantially all” of the general medical conditions they cover. Unlike the earlier law, the MHPAEA imposes tough, detailed coverage parity rules. A plan must offer parity for each classification of benefit.

If, for example, a plan provides unlimited coverage for medically necessary inpatient care for heart attacks, and the plan chooses to cover treatment for depression, the plan must offer unlimited coverage for medically necessary inpatient care for depression.

Plans that violate the MHPAEA parity requirements could face fines of up to $100 per enrollee per day, Halford and Melek report in a written copy of their presentation posted on the SOA website, at http://www.soa.org.

Co-payment levels, coinsurance levels, deductibles, annual visit limits and episode visit limits must be the same for any behavioral health benefits provided as they are for substantially all of the general medical benefits provided, Halford and Melek say.

Milliman has found that plan non-compliance rates for mental illnesses known to be biologically based range from 0% for deductibles for in-network inpatient care to 7% for co-payments for in-network outpatient care.

For other types of behavioral health problems, non-compliance rates range close to 9% for day limits and visit limits, according to Milliman data.

Non-quantitative problems tend to involve issues such as care management procedures and concerns about unequal access to providers of care.

A plan can apply for a cost exemption if complying with the MHPAEA would increase the plan’s costs by more than 2%, but Halford and Melek say it is still too early to know how many employers will seek and qualify for exemptions.

Providing higher-quality behavioral health care, and doing a better job of coordinating behavioral health care and general medical care, could be important to managing overall health care cots, because there appear to be many opportunities to coordinate and improve the quality of both types of care at the primary care level, Halford and Melek say.

Other SOA coverage from National Underwriter Life & Health: