Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008

Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 - (Sec. 2) Amends the Employee Retirement Income Security Act of 1974 (ERISA), the Public Health Service Act, and the Internal Revenue Code to require a group health plan that provides both medical and surgical benefits and mental health or substance use disorder benefits to ensure that: (1) the financial requirements, such as deductibles and copayments, applicable to such mental health or substance use disorder benefits are no more restrictive than the predominant financial requirements applied to substantially all medical and surgical benefits covered by the plan; (2) there are no separate cost sharing requirements that are applicable only with respect to mental health or substance use disorder benefits; (3) the treatment limitations applicable to such mental health or substance use disorder benefits are no more restrictive than the predominant treatment limitations applied to substantially all medical and surgical benefits covered by the plan; and (4) there are no separate treatment limitations that are applicable only with respect to mental health or substance use disorder benefits.

Requires the criteria for medical necessity determinations and the reason for any denial of reimbursement or payment for services made under the plan with respect to mental health or substance use disorder benefits to be made available by the plan administrator.

Requires the plan to provide out-of network coverage for mental health or substance use disorder benefits if the plan provides coverage for medical or surgical benefits provided by out-of network providers.

Exempts from the requirements of this Act a group health plan if the application of this Act results in an increase for the plan year of the actual total costs of coverage with respect to medical and surgical benefits and mental health and substance use disorder benefits by an amount that exceeds 2% for the first plan year and 1% for each subsequent plan year. Requires determinations as to increases in actual costs under a plan to be made and certified by a qualified and licensed actuary.

Requires determinations for such an exemption to be made after such plan has complied with this Act for the first six months of the plan year.

Sets forth requirements for notifications of exemptions under this Act, including notification of the Secretary of Health and Human Services, the appropriate state agencies, and participants and beneficiaries in the plan.

Authorizes the Secretary and the appropriate state agency to audit the books and records of a group health plan relating to an exemption.

Directs the Secretary to: (1) report to the appropriate congressional committees on compliance of group health plans with the requirements of this Act; and (2) publish guidance and information concerning the requirements of this Act and provide assistance concerning such requirements and the continued operation of applicable state law.

Requires the Comptroller General to report to Congress on the specific rates, patterns, and trends in coverage and exclusion of specific mental health and substance use disorder diagnoses by health plans and health insurance.

(Sec. 3) - Amends the Internal Revenue Code to: (1) delay until 2013 the application of special rules for the worldwide allocation of interest for purposes of computing the limitation on the foreign tax credit; and (2) increase the amount of interest allocable to sources within the United States from 30 to 85% in the first taxable year in which the worldwide allocation of interest applies.