Senator Paul Wellstone Mental Health Equitable Treatment Act of 2003

Senator Paul Wellstone Mental Health Equitable Treatment Act of 2003 - Amends the Employee Retirement Income Security Act of 1974 and the Public Health Service Act to prohibit certain employee group health plans or related insurances providing both medical-surgical and mental health benefits from imposing mental health treatment limitations or financial requirements unless comparable limitations and requirements are imposed upon medical-surgical benefits. States that the foregoing shall not be construed as requiring a group health plan (or related insurances) to: (1) provide any mental health benefits; (2) prevent the medical management of mental health benefits; or (3) require the provision of specific mental health services, except to the extent that failure to provide such services would result in a disparity between the coverage of mental health and medical-surgical benefits.

Exempts specified small employers from such requirements.

Requires that, in the case of a group health plan that offers a participant or beneficiary two or more benefit package options, the coverage requirements shall be applied separately with respect to each such option.

Provides that, in the case of a plan or insurance providing in-network mental health benefits, out-of-network mental health benefits need not be provided at parity to medical-surgical benefits, as long as in-network mental health benefits are provided at parity with medical-surgical benefits and the plan or insurance provides reasonable access to in-network providers and facilities.

Requires a General Accounting Office study of such requirements' effects upon health insurance costs, access, and quality and a cost estimation of extending such requirements to the treatment of substance abuse and chemical dependency.