Imagine this scenario: To control costs, a giant health insurer announces that it's singling out heart disease patients. From now on, it will charge them higher co-pays and put lifetime limits on the number of times they can see a doctor for their condition.

The ensuing outrage would be loud and vitriolic. And rightfully so. It's wrong to target one group of patients. And it makes zero sense financially when delaying or denying treatment ultimately leads to higher costs down the road when truly sick patients need technology-intensive procedures that could have been avoided with preventive approaches.

No insurer would propose such severe limits with physical diseases: cancer, diabetes, high blood pressure, autoimmune disorders. But, for years, many have blatantly discriminated against those who struggle with mental disorders. Higher copays and doctor visit limits?

That's reality for many families who struggle with everything from bipolar disorder to anorexia. To make matters worse, some insurers don't provide equivalent out-of-network care for mentally ill patients or put annual or lifetime caps on hospital stays. Mental health advocates for years have sought to fix this imbalance. Along the way they've picked up some powerful champions: the late Sen. Paul Wellstone, D-Minn., Sen. Pete Domenici, R-N.M., and Minnesota Republican Rep. Jim Ramstad. Now it appears a solution is imminent.

On Capitol Hill, the House and Senate are close to key compromises on landmark mental health parity legislation named in honor of Wellstone. Parity means that if your group health plan covers mental health, coverage must be provided on the same terms as medical and surgical care. There cannot be different limitations or financial requirements.

The historic bill, which has the support of many mental health advocates, could arrive at the White House for presidential consideration sometime this month. The Wellstone family and Ramstad deserve praise for their outspoken support and willingness to share their own mental health and addiction experiences.

Ramstad in particular has worked to ensure the compromise bill will truly reform mental health coverage. He has sought key provisions that are expected to appear in the final version. Among them: equivalent out-of-network coverage for mental health patients and a tough enforcement clause for insurers that don't comply with the new law. The version of the bill previously passed by the Senate had neither of these.

Many business groups have long opposed coverage parity, saying costs could drive up premiums substantially. But one estimate by the Congressional Budget Office concluded the impact would be relatively small: a 0.4 percent premium increase for group health insurance. In addition, the federal employees' health plan has had a parity policy since 2001; one study found no significant cost increase as a result. Part of the explanation likely lies in the value of treating mental conditions early and avoiding expensive complications and hospitalization later.

Many states already have laws in place that provide some protection for patients struggling with mental illness or addiction. Minnesota has one of the strongest. A federal law would not preempt those laws. What it would do is make sure no one falls through the cracks. Mental disorders are one of the most devastating diagnoses families can face. Their health insurers should work with them --not against them -- at this difficult time.