WASHINGTON — Rep. Patrick J. Kennedy plans this week to take his signature legislation — a bill to make it easier for mental patients and addicts to get medical coverage — to the floor of the House of Representatives for debate and likely passage.

A majority vote in the House would set up a compromise conference with the Senate, which has already passed a more restrictive version of the legislation to put mental-health insurance on an equal footing with coverage of physical ailments. If the two houses strike a deal, the measure would go to President Bush for his signature.

With a large group of allies from both parties, Rhode Island Democrat Kennedy has framed his bill as a civil-rights issue for a segment of the population long stigmatized by outmoded stereotypes. Too many citizens, Kennedy has argued, are denied the access to affordable mental-health care that has helped him in his own struggle with addiction and manic depression.

But the bipartisan campaign for “mental-health parity,” as it is known in legislative shorthand, is not quite a done deal. The measure’s leading Democratic sponsor in the Senate, Sen. Edward M. Kennedy, of Massachusetts, said last week, “We’ve still got a ways to go.” Backers of the Senate bill say it commands industry support — and therefore a superior chance of enactment — because it would hold down costs more effectively than the House version.

For example, the House version requires coverage of an array of afflictions recognized in the diagnostic manual of the mental-health industry’s professional organization — the fairest approach, supporters say. The Senate uses a narrower list that guides mental-health coverage under government insurance policies. Its supporters say this would be more cost effective.

Supporters of the Senate and House parity bills have had informal discussions for months about possible grounds for compromise because it has long been clear that each version had strong support in its respective house.

The elder Kennedy, father of Patrick Kennedy, led negotiations to develop a consensus parity bill early last year that, for the first time, drew the support of powerful business groups as well as leading mental-health advocates. That bill passed the Senate without opposition last fall under the sponsorship of Kennedy and Sen. Michael B. Enzi, of Wyoming. They are, respectively, the chairman and ranking Republican on the Senate committee with jurisdiction over health issues.

The Senate measure also has such prominent, longtime supporters as retiring Sen. Pete V. Domenici, of New Mexico. Like Patrick Kennedy and other parity advocates, Domenici brings painful experience to the debate: his daughter, Clare, is a schizophrenic. It was while campaigning for Domenici’s last reelection six years ago that Mr. Bush publicly endorsed the principle of parity for mental-health insurance.

Both versions build on a limited mental-health parity law, enacted in 1996, that dealt largely with insurance for government employees. The bills under consideration do not force mental-health insurance upon private carriers. Rather, they require that insurers who offer any treatment for mental illness must use the same basic rules that they apply to the treatment of cancer or broken bones or other physical ailments.

For example, a managed health-care company cannot impose a higher copayment for a session with a clinical psychologist than it charges the same patient for a visit to the internist.

Health-care coverage of mental illness has long been freighted with higher costs and treatment limitations than traditional medical-surgical insurance.

Patrick Kennedy has taken a highly personal approach to the campaign for the parity bill that he sponsored with Rep. Jim Ramstad, Republican of Minnesota — an alcoholic who has not taken a drink since what he calls his “wake-up call,” a humbling episode of public drunkenness more than 25 years ago.

Kennedy disclosed some years ago that he is under treatment for bipolar illness. The disorder subjects sufferers to extreme shifts of mood, from deep depression to high exhilaration or mania — hence the term manic depression, by which it is also known. In May 2006, he acknowledged his alcoholism and drug dependence after he crashed his car into a Capitol Hill police barrier while under the influence of prescription pills.

Kennedy sought hospital treatment and, after his return to work the next month, introduced House colleague Ramstad as his sponsor in the 12-step lay recovery program that they share. Early last year — in what Kennedy has described as a valuable tool for staying free of drugs and alcohol — he and Ramstad conducted a series of hearings around the country to promote support for their parity bill.

Later, Ramstad and Kennedy steered the bill to passage through three House legislative panels that share jurisdiction over health care — a process that has improved chances that some of the measure’s more expansive provisions can survive in the eventual compromise with the Senate version, according to Kennedy.

The process featured some pointed criticism of the Kennedy-Ramstad bill that may recur in a House-Senate conference over the conflicting parity measures.

“There must have been a similar debate at the kitchen table between the senator and the congressman — both by the name of Kennedy,” Rep. Frank J. Pallone, Democrat of New Jersey, joked late in October as the Kennedy-Ramstad bill was sent to the full House on a lopsided, bipartisan vote of the Energy and Commerce Committee.

The full House debate and vote on the Kennedy-Ramstad bill is scheduled for Wednesday.

jmulligan@belo-dc.com