Sleep hits pothole on lonely street. (Behavior).

Lonely people often get a lousy night's sleep, according to a new study. Lack of high-quality slumber among the lonesome may contribute to their elevated physical illness and death rates, say psychologist John T. Cacioppo of the University of Chicago and his coworkers.

Data for the study came from 33 male and 21 female college students who spent a night in a sleep laboratory wearing a cap fitted with sensors that measure eyelid movements, head rolls, and brain waves. Participants then wore the cap at home for 5 consecutive nights. On a questionnaire about the number and quality of a person's social relationships, 16 students ranked as lonely, 21 had a rich social life, and 17 fell between those extremes.

Men and women reporting either no, some, or pervasive loneliness slept for about the same amount of time each night, the researchers note. However, only the loneliest individuals of both sexes awakened more often during the night and spent less time in deep sleep than those in either of the other two groups did, Cacioppo's group concludes in the July Psychological Science.

Lonely feelings may have impaired peaceful slumber, the researchers say. It's also possible that fatigue and distress from sleep problems undermine social skills, thus boosting loneliness.--B.B.