How do you boost a flagging pipeline? One strategy is to enlist more researchers to find promising drug candidates. Two heads are better than one, and the more minds applied to the task, the more likely they will find increasingly elusive new therapies. The Pfizer–Wyeth and Merck–Schering Plough mergers are partly based on this premise.

Trouble is, the premise might not hold water.

Mergers sometimes end up hindering innovation by creating a large bureaucracy, according to Joseph Schlessinger, chairman of the pharmacology department at Yale’s School of Medicine. The reorganization that inevitably follows a big merger is often disruptive enough to inspire coveted scientists to seek jobs elsewhere.

“It’s impossible to organize and be productive while running such a large group of scientists,” Schlessinger told the Philadelphia Inquirer. “They stop working and they talk all the time and they start to look for jobs and they are really worried. It’s extremely counterproductive for a long time, and it’s demoralizing.”

Pfizer’s own history lends credence to this conclusion. The company reaped short-term benefits after acquiring Warner-Lambert and Pharmacia, but its enlarged research budget did not yield the anticipated cornucopia of new candidates. “Even after acquiring these companies, Pfizer’s research program is mediocre at best for a company its size,” said Daniel A. Hussar, a professor at Philadelphia’s University of the Sciences, to the Inquirer.

It might not be enough for a pharmaceutical company to simply accumulate a big team of great minds. If pipelines are to flourish again, drugmakers must bring their researchers a sense of security, encourage them to take chances, and give them room to experiment.