Members of the Senate Health, Education, Labor and Pensions Committee voted 18-3 today to pass a bill that could require insurers to offer the same level of coverage for mental health care that they offer for physical health care.

S. 558, the “Mental Health Parity Act,” would apply to both treatment of conditions such as depression and of substance abuse problems such as alcoholism.

Under the terms of S. 558, parity “means no limits on days or treatment visits, and no exorbitant co-payments or deductibles,” says Sen. Edward Kennedy, D-Mass., HELP Committee chairman.

Kennedy cited estimates that mental illness costs the U.S. economy about $300 billion annually in treatment costs, lost worker productivity and crime, and he also cited a study showing that one large employer reaped a 4-to-1 return on investment when it decided to offer the same level of benefits for mental illness that it had been offering for physical illness.

“This country can afford mental health parity,” Kennedy said. “What we can’t afford is to continue denying persons with mental disorders the care they need.”

Sen. Mike Enzi, R-Wyo., the most senior Republican on the HELP Committee, also praised the bill, noting work by lawmakers to keep the costs of mental health care from becoming a burden for employers.

But Sen. Tom Coburn, R-Okla., an obstetrician, predicted the bill would have unintended negative consequences.

The most serious problem in mental care is a lack of available, trained psychiatrists, “and I don’t see that this bill is going to be solving that problem,” Coburn said. “We’re taking all the market forces away. We’re taking the competition away.”

Sen. Richard Burr, R-N.C., complained that committee staffers took till Tuesday to respond to technical questions about the bill, even though he had asked the questions a week ago.

Kennedy said the committee would work on the bill as it moves toward the Senate floor, but Burr objected to that approach.

“Perfecting a bill, especially on the technical side, is not something you do on the floor,” Burr said. “You do it in committee.”

But the American Benefits Council, Washington, an employer group that usually opposes benefits mandates, is supporting the bill.

“We consider it a more moderate version of previous attempts to legislate mental health parity,” ABC President James Klein says in a statement. “It earned our support because it imposes no mandates on the services or conditions a plan must cover, permits plans to contract with separate networks of mental health providers to deliver covered services, allows plans to employ a wide range of medical management practices to help ensure that only medically necessary care is covered and preempts state laws that ‘differ from’ the federal requirements.”

But the ABC is urging that the bill be approved as is, to reduce the risk that Congress will weaken or remove the employer and health plan “protection provisions” now in the bill, Klein says.

Aetna Inc., Hartford, a managed care company with a behavioral health operation, also has come out in support of the bill.