NEW YORK (Reuters) - U.S. stocks fell in choppy trade and the Nasdaq closed at its lowest level since October 2002 on Monday as shares of the biggest drugmakers fell after Merck's proposed $41 billion takeover of Schering-Plough .
* Large mergers and acquisitions are generally viewed as a show of support for equity valuations, but analysts said with major indexes trading around 12-year lows, evidence of thawing credit markets and economic recovery is needed to bring investors back into the market.
* The Dow Jones industrial average <.DJI> fell 79.89 points, or 1.21 percent, to end unofficially at 6,547.05. The Standard & Poor's 500 Index <.SPX> lost 6.85 points, or 1.00 percent, to 676.53. The Nasdaq Composite Index <.IXIC> shed 25.21 points, or 1.95 percent, to 1,268.64.
(Reporting by Leah Schnurr; Editing by Jan Paschal)
