H.R. 4066 is basically identical to the version of S. 543 which was offered as an amendment to the FY2003 Labor-Health and Human Services-Education appropriations bill by Senators Domenici (R-NM) and Wellstone (D-MN), agreed to by the full Senate in October, and stripped out of the conference report by House Republicans in December.

Last January, Representative Roukema had introduced H.R. 162, the Mental Health and Substance Abuse Parity Amendments of 2001, which had included coverage for substance abuse disorders, while S. 543 did not. Given the fact that 224 Representatives had signed a letter in support of the retention of the Domenici-Wellstone Amendment in the Labor-Health and Human Services FY2003 Appropriations Conference Report which did not contain the substance abuse provisions, Representative Roukema decided to make a statement and formally introduce on the House side the language that enjoys widespread support.

H.R. 4066 would expand upon the 1996 Mental Health Parity Act by providing full parity for all categories of mental health conditions listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), subject to medical necessity. Health insurance plans would be forbidden from applying different deductibles, co-payments, out-of-network charges, inpatient day and outpatient visit limits for mental health care than those for medical and surgical health care, if mental health benefits are offered. Like the 1996 Act, none of the bills would mandate that plans offer mental health benefits if they currently do not. Small businesses with fewer than 50 employees would be exempted.