Relationship between ethnicity and sleep patterns in normal controls: implications for psychopathology and treatment

The purpose of the study was to examine ethnic influences on sleep regulati on. Seventy-three normal volunteers from four ethnic groups (17 African-Ame ricans, 10 Asians, 30 Caucasians and 16 Hispanics) were studied for two con secutive nights with sleep polysomnography recordings in the laboratory. Th e subjects were in good physical and psychological health, and were asympto matic with respect to sleep/wake complaints or sleep disorders. With the ex ception of minor differences, sleep continuity, sleep architecture and rapi d eye movement (REM) sleep patterns were comparable among the four groups. African-Americans had evidence of more stages 1 and 2 and diminished stage 4 sleep, whereas the Hispanics had higher REM density. These preliminary fi ndings suggest that sleep patterns are remarkably similar across cultures. There are, however, important cross-ethnic differences, specifically in the depth of sleep and in phasic REM measures. Because sleep disturbances are common symptoms of emotional disorders and since many psychoactive agents a ffect sleep, cross-ethnic differences in sleep patterns may have potential implications for the treatment and prevention of psychiatric disorders. (C) 1999 Elsevier Science Ltd. All rights reserved.