WASHINGTON, April 23  Lawmakers began weighing ways Monday to prevent more tragedies on college campuses in a hastily convened Senate hearing a week after the shootings in Virginia. The hearing explored the adequacy of campuses’ mental health resources, security plans and communications systems.

“We are here to begin a discussion, in the aftermath of Virginia Tech, to make sure that we are doing everything we can to prevent any other campus and any other students and their families from experiencing the nightmare and loss Virginia Tech experienced,” said Senator Joseph I. Lieberman, a Connecticut independent who is chairman of the Committee on Homeland Security and Governmental Affairs.

Some of the most disturbing testimony came from Russ Federman, director of counseling and psychological services at the University of Virginia.

Dr. Federman ticked off statistics from a recent survey about the extent of mental health problems on campuses. He said that 94 percent of students reported feeling overwhelmed by all they have to do, and that nearly 50 percent reported having felt so depressed that it was difficult to function.