A bill calling for parity health coverage for addiction and mental illness is expected to pass the U.S. House of Representatives on March 5, with advocates urging supporters to call their lawmakers and a Capitol Hill rally planned with major Congressional leaders prior to the vote.

House Speaker Nancy Pelosi (D-Calif.) is slated to appear Wednesday at the 1 p.m. rally and press conference in support of the Paul Wellstone Mental Health and Addiction Equity Act (H.R. 1424), a good sign that the bill -- which has 274 cosponsors -- is expected to pass later in the day.

Pat Taylor, director of Faces and Voices of Recovery, said that hundreds of recovery advocates from the D.C. area, Maryland, New Jersey and elsewhere are expected to attend the rally. Former First Lady Rosalynn Carter also is expected to attend.

Faces and Voices and the group Wellstone Action -- led by David Wellstone, son of the late senator from Minnesota -- have been organizing a call-in campaign ahead of the vote. "We're very hopeful of a positive outcome with strong bipartisan support," said Taylor.

The House legislation is cosponsored by Reps. Patrick Kennedy (D-R.I.) and Jim Ramstad (R-Minn.). The Senate passed its version of mental-health parity legislation, S-558, last fall; that measure, cosponsored by Sens. Ted Kennedy (D-Mass.) and Pete Domenici (R-N.M.), is generally viewed as more of a compromise than HR-1424, which has garnered opposition from the business community over cost concerns.

If the House bill passes, differences with the Senate bill will need to be worked out before final legislation can be sent to the president. Advocates say that quick action is needed if parity legislation is to be signed into law during the current Congress since the general election this fall will shorten the legislative session.