Sleep disorders affect millions of Americans and often cause accidents and ruin careers. However, they usually are ignored by physicians, and victims may go years without treatment.

In a hearing on Capitol Hill of the National Commission on Sleep Disorders Research, victims and experts said Tuesday that more attention must be paid to the suite of sleep ailments that can cripple lives, end marriages, disrupt careers and even cause death."The need for sleep research is virtually ignored," said William C. Dement, chairman of the commission and a medical professor at Stanford University. "The house of research does not have a bedroom."

Sleep disorders range from an irresistible urge to sleep - an ailment called narcolepsy - to insomnia, which is the inability to achieve adequate or restful sleep. Other problems include "restless leg syndrome," the jerking and twitching of the lower limbs during sleep; snoring, which may be habitual for almost half of all adults, and sleep apnea, a disorder in which breathing stops and restarts through the night, disturbing rest and perhaps causing death in some victims.

People also suffer from sleep disorders caused by travel and work schedules that disturb the natural rest-wake cycle. Sleep cycle changes may pose a particular hazard in modern society, the experts said.

David Dinges, a University of Pennsylvania psychologist, said poor sleep and the resulting lack of alertness is becoming a major element in industrial accidents, particularly for shift workers, jet travelers who cross many time zones and those working too many hours.

"Inadequate sleep is a major cause of human error, and at least as important as drugs, alcohol and equipment failure" in workplace accidents, he said.

Dinges said airplanes, ships, factories and power plants all are becoming increasingly automated, which means humans must sit and alertly monitor what the machines are doing.

"That's a task we do poorly after missing some sleep, especially if we have to work at night," he said.

Dinges said industry and the military are beginning to recognize the need to shift work hours to allow for the human need to adjust sleep cycles to new schedules.

He said the use of bright lights to readjust sleep cycles "shows promise." Allowing pilots to nap in the cockpit has been shown useful in keeping them alert during long transoceanic flights, he said. But other proposed treatments, such as special diets, have proven useless in treating the fatigue of jet lag and night shift work.

Sufferers of narcolepsy testified they must constantly fight the tendency to suddenly drop off to sleep, often at the very worst of times.

Lori Highland of Ashford, Wash., said she has spent her life "in a haze of sleepiness."

"My life is haunted by this," she said. "I can't drive. I have been hospitalized repeatedly for injuries" that occur when she collapses suddenly into sleep.