The Mental Health Parity Act (MHPA) is legislation signed into United States law on September 26, 1996 that requires annual or lifetime dollar limits on mental health benefits to be no lower than any such dollar limits for medical and surgical benefits offered by a group health plan or health insurance issuer offering coverage in connection with a group health plan. Prior to MHPA and similar legislation, insurers were not required to cover mental health care and so access to treatment was limited, underscoring the importance of the act. The MHPA was largely superseded by the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act (MHPAEA), which the 110th United States Congress passed as rider legislation on the Troubled Asset Relief Program (TARP) in Public Law 110-343, signed into law by President George W. Bush in October 2008. Notably, the 2010 Patient Protection and Affordable Care Act extended the reach of MHPAEA provisions to many health insurance plans outside its previous scope. Scope The MHPA applies to group health plans for plan years beginning on or after January 1, 1998. The original sunset provision provided that the parity requirements would not apply to benefits for services furnished on or after September 30, 2001. It was extended six times, with the final extension running through December 31, 2007. Insurers promptly were able to "circumvent" the consumer protections arguably intended in the legislation by imposing maximum numbers of provider visits and/or caps on the number of days an insurer would cover for inpatient psychiatric hospitalizations. In essence, the law had little or no effect on mental health coverage by group insurance plans. The rider on TARP prohibits all group health plans that offer mental health coverage from imposing any greater limit on co-pays, co-insurance, numbers of visits, and/or number of days covered for hospital stays due to mental health conditions. The rider legislation was the culmination of a long campaign fought by Sen. Paul Wellstone (D-MN) and his successors to enact mental health parity at the federal level. The new law's requirements will be phased in over several years. Still unsure is whether non-"biologically-based" mental illnesses such as PTSD and eating disorders are mandated to be covered by the new law. Requirements Generally the act required parity of mental health benefits with medical and surgical benefits with respect to the application of aggregate lifetime and annual dollar limits under