Thomas Thorne
WASHINGTON, Aug. 5 (UPI) — Working at night and sleeping during the day is not natural for any human body, but some people have trouble adjusting to such arrangements to the point where their distress qualifies as a medical disorder. Now, this underdiagnosed and difficult-to-treat condition is the subject of the first clinical trial of the promising drug modafinil.
Shift work sleep disorder is characterized by drowsiness during night work hours, insomnia when trying to sleep during the day, and cases of fatigue-induced work accidents and errors in people whose work shifts include more than six hours between 10 p.m. and 8 a.m. The effects include higher rates of accidents, absenteeism, depression, ulcers, and frequent lack of family and social activities.
Charles Czeisler, lead author of the study, which appears in the Aug. 4 issue of the journal New England Journal of Medicine — told United Press International that the condition affects 5 to 10 percent of night shift workers. It is also often underdiagnosed because it is confused with normal fatigue.
Czeisler compared the difference between normal tiredness and disarray to the scene at tourist destinations, where some travelers walk around examining landmarks and others slump on benches due to the effects of jet lag.
"Some people are more affected than others," he said.
David Dinges, head of the Division of Sleep and Chronobiology at the University of Pennsylvania in Philadelphia and co-author of the paper, told UPI that he has been conducting another study. This one, sponsored by the National Institutes of Health, examines healthy people who do not work shifts and who have spent non-consecutive nights without sleep.
He said he found that participants who experienced great difficulty during their first sleepless night also had difficulty on subsequent sleepless nights, regardless of how much sleep they slept in the interim. At the same time, participants who remained relatively functional after their first night of insomnia retained that ability on other nights when they stayed awake.
"This is a trait-like characteristic of people," Dinges said.
Czeisler, chief of sleep medicine at Brigham and Women's Hospital in Boston and professor of medicine at Harvard Medical School, said that in addition to revealing a possible treatment, another notable aspect of the study was its findings on the effects of switching. work sleep disorder.
"It revealed how sleepy this group of patients is," Czeisler said. "They are as sleepy as patients with narcolepsy or sleep apnea."
In the study, researchers assigned 209 patients with sleep disorders who worked shifts to receive 200 milligrams of modafinil or a placebo before the start of each work shift. Modafinil is sold under the brand name Provigil and is manufactured by Cephalon Inc., which provided research funding to Czeisler. The medication is also used for narcolepsy and sleep apnea.
The study measured sleep latency and attention lapses. Sleep latency is the time it takes for a person to fall asleep if given the opportunity.
Czeisler said that during the day, falling asleep in less than five minutes means excessive sleepiness. No standards have been developed for healthy nighttime sleep latency, so the sleep latency figures collected in his study simply served as a measure of change. The average decrease in sleep latency for patients receiving modafinil was 1.7 minutes, compared to 0.3 minutes for the placebo group. The difference in sleep latency was most pronounced early in the night, around 2 a.m., and decreased around 6 a.m.
To monitor attention failures, the Psychomotor Vigilance Test was used. Patients in the modafinil group experienced a mean rate of 2.63 fewer attention lapses per 20-minute trial, while patients in the placebo group experienced 3.75 more attention lapses than before receiving the placebo.
Patients in Czeisler's study worked in a wide variety of occupations, including manufacturing, investment banking, police work, and hospital nursing.
“One thing that was common to all of them was actual or near-accidental car accidents while driving home from work,” Czeisler said.
Among the study's placebo group, 54 percent reported accidents or near-misses during their trip home, while only 29 percent of patients receiving modafinil reported such incidents.
Czeisler acknowledged that although modafinil is useful, it does not allow for perfect functioning.
"This takes (patients) about a third of the way to normal during the day, but we don't know what is normal during the night," he said. Additionally, patients in the modafinil group experienced daytime insomnia at a rate 6 percent higher than the placebo group.
Czeisler said the brain sends a strong impulse to sleep at night and that it is contrary to the body's circadian rhythms to work at night and sleep during the day, but modern life sometimes requires the suppression of biological directives.
"There are many essential services provided by people who work at night, and we live in a society that requires many 24-hour operations," Czeisler said.
Dinges said that with the number of shift workers in the United States at 6 million and rising, it would be economically unfeasible to exclude even people with innate difficulties from night shift work, even though numerous government and scientific studies point to dangerous consequences of such activities, such as industrial accidents and road collisions.
"I don't know how realistic it is to suggest that vulnerable people shouldn't work the night shift," she said.
Other doctors suggest that more possibilities may be found to control the disorder.
Robert Basner, associate professor of clinical medicine at Columbia University, wrote in the NEJM article that other researchers' findings show that doses of 600 mg of caffeine can produce effects similar to modafinil in improving performance in people who have been awake for more than 40 hours, and according to Czeisler's study, modafinil does not affect the underlying circadian rhythm.
"Neither these data nor any other published studies provide evidence indicating that modafinil is particularly suitable for use as a wakefulness and alertness enhancer in humans undergoing night shift work," Basner wrote.
Czeisler said he did not test (nor would he personally defend) the drug's potential to keep people awake for indefinite periods of time, such as studying all night.
Dinges said caffeine and bright lights have been used for years to treat shift work sleep disorder, but have not been tested in many experiments.
"In the experiments in which they have been tested, they have limited usefulness," he said. He agreed that more research needs to be done on this disorder and standards set for normal levels of nocturnal alertness.