Journal of Youth and Adolescence, Vol. 13, No. 5, 1984
Sleep Disturbance in Adolescents: Sleep Quality, Sleep Habits, Beliefs About Sleep, and Daytime Functioning Kathleen KirmiI-Gray,~ Jean R. Eagleston, Elizabeth G i b s o n , and Carl E. Thoresen 2 Received July 2, 1984; accepted for publication July 25, 1984
This study examined the prevalence and correlates o f sleep disturbance in adolescents. Two hundred seventy-seven 9th- and lOth-grade students completed a questionnaire on sleep quality, sleep habits, beliefs about sleep, and daytime mood and functioning. Based on their responses, subjects were classified as good sleepers (66%), occasional poor sleepers (23%), and chronic poor sleepers (11%). Occasional and chronic poor sleepers reported being significantly more depressed, without energy, tense, moody, and irritable and less rested and alert than good sleepers. They were also more likely to describe themselves negatively. However, poor sleepers were not consistently more tired than good sleepers. Rather, they tended to be least tired in the evening, the time when most good sleepers reported feeling tired. There weref e w differences in the sleep habits and beliefs about sleep o f good and poor sleepers. All subjects reported shifts in bedtimes and waketimes from weekdays to weekends, with occasional and chronic poor sleepers showing a tendency toward greater shifts, a possible factor contributing to their sleep disturbance. Occasional and chronic poor sleepers also reported more observable behaviors and feelings o f stress than good sleepers. The need for early intervention with particular attention to teaching adolescents about good sleep habits and the need f o r stable bedtimes and waketimes and the possibility of joint intervention on daytime stress and sleeping problems are discussed. This research was supported by NIMH Grant MH27551. We gratefully acknowledge Kristen Thoresen and Daytime Stress and Sleep Project staff for their help in conducting this study. We also thank Mary Carskadon for her comments and suggestions on the manuscript. ~Research Associate, Center for Educational Research, Stanford University, Stanford, California. Received her Ph.D. from Stanford University and is currently Director of the Health in Youth Project, a study of chronic stress and Type A behavior in children and
adolescents. ZTo whom correspondence should be addressed at School of Education, Stanford University, Stanford, California 94305. 375 0047-2891/84/1000-0375503.50/0 © 1984 Plenum Publishing Corporation
376
KirmiI-Gray, Eagleston, Gibson, and Thoresen
INTRODUCTION Between 15 and 50°70 of adolescents report at least occasional difficulty falling asleep or staying asleep, with 7-13°70 of this age group experiencing chronic and severe insomnia (Price et al., 1978; Korlath et al., 1976; Karacan et al., 1976; Hauri and Sobel, 1977; White et aft, 1980). Although few adolescents seek help for sleeping problems, the prevalance of disturbed sleep among youth is of some concern because retrospective studies and clinical anecdotes of adult insomniacs suggest that insomnia often begins early in life and persists into adulthood. Hauri and his colleagues (Hauri et al., 1980) found that 47070 of adult insomniacs reported their sleeping difficulties to have begun in childhood or adolescence, while Bixler and his associates (Bixler et al., 1979) calculated that 18070 of their sample experienced significant difficulty sleeping before the age of 20 years. The possibility of early intervention when sleeping problems may be less severe and more amenable to change has led a few investigators to study the correlates of sleep disturbance in adolescence (Price et al., 1978; Marks and Monroe, 1976; Bertelson and Monroe, 1979; Hauri and Sobel, 1977). Price and her colleagues examined the sleep habits, daytime feelings, and self-perceptions of 627 normal high-school students. They found few differences in the sleep habits or nighttime routines of good and poor sleepers but marked differences in their daytime experience. Poor sleepers reported being more tired, depressed, tense, moody, and irritable than good sleepers, with those complaining of chronic and severe insomnia showing the greatest frequency of daytime disturbance. Poor sleepers also tended to describe themselves more negatively. In a study of 394 normal 19 year olds, Hauri and Sobel (1977) found teenage insomnia to be related to anger, depression, school adjustments, and life stress. The present study was designed (I) to replicate partially the findings of other investigators regarding the sleep habits, feelings, and self-perceptions of normal adolescents with sleeping problems, (2) to investigate the beliefs and misconceptions that adolescents hold about sleep, and (3) to examine the relationship between chronic stress and sleep disturbance in adolescents.
METHOD
Subjects were 277 students in the 9th and 10th grades enrolled in required health classes in three senior high schools in the San Francisco Bay Area. They were told that researchers at Stanford University were interested in learning about the stress and sleep patterns of young people and were asked
Sleep Disturbance in Adolescents
377
to fill out a questionnaire during their regular class period. Approximately equal numbers of girls and boys participated in the study (girls, N = 146; boys, N = 130). They ranged in age from 13 to 17 years, with a mean age of 15 years; 65% were freshmen, and 35°7o sophomores. The questionnaire assessed perceived sleep quality, sleep habits and environment, beliefs about sleep, and daytime mood and functioning. Subjects who reported disturbed sleep were asked to complete an additional section on the management of their sleeping problem.
RESULTS Prevalence of Disturbed Sleep Students were divided into three groups on the basis of their responses to questions about sleep quality. Group 1, chronic poor sleepers (30 students; 11%), reported at least one of the following problems 3 or more nights per week: (I) taking 45 rain or longer to fall asleep, (2) awakening three or more times per night, and (3) staying awake during the night for 30 min or more. These criteria have been used to discriminate good and poor sleepers and thus allow comparisons between the results of this study and those of other studies (Price et al., 1978; Carskadon et al., 1976). Group 2, occasional poor sleepers (63 students; 23%), reported some sleeping difficulties but did not meet the criteria of the chronic poor sleepers. Group 3, good sleepers (184 students; 66%), reported no sleeping problems. Differences between groups were assessed by chi-square analyses and one-way analysis of variance as appropriate. Table I presents data on the prevalence of sleep disturbance among these young adolescents. Similar to other studies of both adolescents and adults, significantly more girls (41%) than boys (25%) reported sleeping difficulties (p < 0.02), with the greatest sex differences found among occasional poor sleepers. Chronic poor sleepers reported more severe and more frequent sleep disturbance of all types. Problems falling asleep were most common. However, even at their young age, a notable percentage of occasional (25%) and chronic poor (37%) sleepers complained of difficulties maintaining sleep. Chronic poor sleepers reported significantly shorter total sleep times than either occasional poor or good sleepers. Most occasional (52.6%) and chronic poor sleepers (62.1%) had problems sleeping for a year or more, and some considered their problem severe or very severe (1.7, 17.9%).
378
KirmiI-Gray, Eagleston, Gibson, and Thoresen Table 1. Prevalence and Description o f Sleep Disturbance A m o n g Y o u n g Adolescents Percentage
Characteristics Males Females Difficulty falling asleep 3 or m o r e n i g h t s / w e e k 45 m i n or m o r e Difficulty staying asleep 3 or more nights/week 3 or more awakenings A w a k e 30 m i n or m o r e D u r a t i o n of sleeping p r o b l e m > 1 year Severity Severe or very severe T o t a l h o u r s slept
Good sleepers ( N = 184)
Occasional poor sleepers ( N = 63)
Chronic poor sleepers ( N = 30)
74.6 58.9 0 --0 -
16.2 28.8 63.5 18.0 33.3 25.4 4.8 9.5 19.0
9.2 12.3 93.3 90.0 80.0 36.7 20.0 13.3 20.0
-
52.6
62.1
1.7 7.9
17.9 7.0
7.8
Daytime Feelings and Mood Significant differences in the daytime feelings and mood of good and poor sleepers are reported in Table II. Occasional and chronic poor sleepers reported feeling more depressed, tense, without energy, moody, irritable, less rested, and less alert than good sleepers. They were also more likely to use negative adjectives to describe themselves, suggesting a negative self-image. Interestingly, poor sleepers were not consistently more tired during the day than good sleepers. There were no significant differences between groups in the percentage of students feeling tired in the morning; most subjects reported feeling tired in the morning. However, more occasional and chronic poor sleepers reported feeling tired during the afternoon, a trend that reversed itself in the evening, when fewer chronic poor sleepers reported feeling tired than occasional or good sleepers. When asked if they considered themselves "a night person," more occasional and chronic poor sleepers responded positively, although the differences were not significant statistically (52.0, 61.9, and 69.0%).
Sleep Habits and Environment There were few differences in the sleep habits or sleep environments of good and poor sleepers. Reading, watching television, studying, and listening to music in bed and taking naps were no more common to poor sleepers
Sleep Disturbance in Adolescents
379
Table !1. Daytime Feelings of Good, Occasional Poor, and Chronic Poor Sleepers Percentage
Tired in morning Tired in afternoon Tired in evening Depressed Without energy Tense Moody Irritable Rested Alert Negative personal description
Good sleepers (N = 184)
Occasional poor sleepers (N = 63)
Chronic poor sleepers (N = 30)
X2
78.8 41,5 53.1 36,0 35.1 37.3 23.4 6.5 50.0 47,3 3.6
85.7 65.0 56.7 66.7 49.2 53.3 36.5 9.5 23.8 28.6 t0.2
90.0 72.4 30.0 66.7 53.3 53.3 43.3 23,3 20.0 26.7 24.1
NS 16.3a 6.4* 22.3 a 6.0* 6.2* 7.6* 8.94 19.4 a 9.6 b 35.9 ~
°p < 0.05.
~p < 0.01. ~p < 0.001. ap < 0.0001.
than good sleepers. Occasional and chronic poor sleepers did report drinking more caffeinated beverages per day than good sleepers (I .2, 1.7, and 1.8 cups; p < 0.05) and eating in bed 1 or more nights per week (20, 36, and 45°/0; p < 0.01). Chronic poor sleepers were also more likely to complain of a moderate or noisy sleep environment (47%0) than either occasional poor (22%) or good (20°70) sleepers. Interestingly, physical problems such as allergies that might be expected to interfere with sleep as well as recurrent dreams and nightmares were most common among occasional poor sleepers [physical problems-20.7, 41.3, and 31.0°-/o (p < 0.01); recurrent dreams-6.1, 17.7, and 13.3% (p < 0.02); nightmares-1.7, 8.1, and 0.0% (p < 0.02)]. Both occasional and chronic poor sleepers were more likely than good sleepers to experience crawling sensations in their legs and leg jerks, suggesting the possibility of physiological causes such as nocturnal myocionus and restless leg syndrome for sleep disturbance [crawling sensations- 1.1, 6.5, and 6.707o (p < 0.04); leg jerks-7.3, 16.1, and 16.7°70 (t9 < 0.07)]. All subjects reported significant shifts in bedtimes, waketimes, and total sleep time from weekdays to weekends. They tended to go to bed 1.7 hr later (p < 0.001) and get up 2.7 hr later (17 < 0.001) on weekends than weekdays, thus increasing their total sleep time on weekends by 1 hr. Figure 1 displays the significant linear trend in bedtime and waketime shifts found. Chronic poor sleepers showed the greatest shifts, occasional poor sleepers the next greatest shifts, and good sleepers the smallest shifts [bedtime s h i f t - 1.6, 1.9, and 2.1 hr (p < 0.05); waketime shift-2.6, 2.9, and 3.1 hr (17 < 0.03)]. However, differences between groups were not significant.
380
KirmiI-Gray, Eagleston, Gibson, and Thoresen 4 hours
Waketime shifts
3 hours
Bedtln~ shifts
f ~
2 hours
J | hour
Good
Sleepers
Occasional
Poor Sleepers
Chronic Poor
Sleepers
Fig. 1. Shifts in bedtimes and waketimes from weekdays to weekendsof good, occasional poor, and chronic poor sleepers.
Beliefs A b o u t Sleep
To explore the relationship between beliefs about sleep and sleep disturbance, subjects were asked if they agreed or disagreed with several statements about sleep. Subjects as a group held several misconceptions about sleep and daytime feelings. Most of these misconceptions related to the relationship between nighttime sleep and daytime functioning and the possibility of making up or storing up sleep. People need at least 8 hours of sleep. (Agreement = 61%.) Without enough sleep, you will not function well during the day. (96%) If you feel tired during the day, you must not have slept well the night before. (48070) If you don't get enough sleep on a particular night, you have to make it up at another time. (40°70) If you know you won't be getting enough sleep, you can prepare by sleeping more hours on preceding nights. (50%) Only four beliefs discriminated significantly between groups as shown in Table III. Occasional poor sleepers were less aware than good or chronic poor sleepers that the number of hours people need to sleep varies from person to person but were more aware of the dangers of sleeping pills. Both
Sleep Disturbance in Adolescents
381
Table !!!. Beliefs A b o u t Sleep That Differentiate Good, Occasional Poor, and Chronic Poor Sleepers Percentage
People have an individual a m o u n t of sleep they need to feel rested. (True) Most sleeping pills are harmless. (False) Changes in noise, light, or surroundings will interfere with sleep. (True) I ought to be able to sleep welt regardless o f what is going on in my life. (False)
Good sleepers (N = 184)
Occasional poor sleepers (N = 63)
Chronic poor sleepers (N = 30)
X~
95.1
85.7
96.7
7.1 *
23.0
9.8
25.1
5.2 a
68.5
82.5
86.7
7.7 ~
41.0
20.6
26.7
9.5 b
"p < 0.05. bp < 0.0I.
groups of poor sleepers were aware that changes in the environment could affect sleep and were less likely to feel that they should sleep well regardless of what was going on in their lives.
Daytime Stress and Sleep Disturbance Significant differences in the daytime stress of good and poor sleepers are reported in Table IV. All individual items, as well as the total score, showed a significant linear trend, with chronic poor sleepers generally reporting the most signs of daytime stress, occasional poor sleepers the next most, and good sleepers the least. Poor sleepers reported more observable signs and feelings of stress and spent more time worrying, thinking about two things at once, and thinking about something else when talking with someone than good sleepers. They also tended to be more emotionally labile, to think more negative thoughts, and to hold more beliefs that might be expected to cause stress (for example, "I often struggle to prove myself" or "I often feel dissatisfied with how well I am doing"). Sleep-disturbed subjects were also more likely to report displaying characteristics of the Type A behavior pattern.
Management of Sleeping Problems Of occasional and chronic poor sleepers, nearly 60°/0 believed that the quality of their day affected the way they slept at night. Having a good day
382
KirmiI-Gray, Eagleston, Gibson, and Thoresen
Table IV. Self-Reported Daytime Stress of Good, Occasional Poor, and Chronic Poor Sleepers
Observable signs of stress* Feelings of stress Emotional lability Stress-producing beliefs
Good sleepers (N = 184)
Occasional poor sleepers (N-- 63)
Chronic poor sleepers (N = 30)
F
1.2 3.2 2.9 4.6
2.8 5.5 4.2 6.5
2.2 5.2 4.2 7.5
12.0a 13.5" 11.I" 13.6~
6.3
7.1
7.2
2.5c
5.3
5.9
6.5
3.6c
Does two or more things at onceb Thinks about other things when someone is talking Engages in negative thoughts about self Worries about getting everything done Considers oneself Type A
6.4
7.1
8.3
6.8~
6.4 5.7
6.8 6.7
7.8 6.2
3.9c 3.9"
Total daytime stress score
16.4
23.8
24.1
21.1"
"Frequency. bRatings on a 12-point scale from almost never (1) to almost always (12). Cp < 0.05. dp < 0.01.
~p < 0.001.
or exercising was t h o u g h t to lead to a g o o d night's sleep, while having m u c h on their minds or having had an a r g u m e n t were reported to result in disturbed sleep. Most subjects (62.707o) also believed that how well they slept influenced their functioning the next day; p o o r sleep was associated with feeling tired, irritable, m o o d y , and lazy. A variety o f remedies was used to m a n a g e sleeping problems including listening to the radio (85070), reading (75.3070), focusing t h o u g h t s on something specific (69.6070), watching television, (52.6070), and relaxing systematically (52.907o). All were reported to w o r k at least sometimes. Subjects were less inclined to use medication or alcohol to help themselves sleep, a l t h o u g h 14.9070 o f those with disturbed sleep had used medication at least once, and 16.4070 had used alcohol, with 907o reporting use o f both. Medication and alcohol use did not covary with the severity o f sleep disturbance. H a l f o f the subjects w h o reported having taken medication had used aspirin, while the other half h a d used either over-the-counter or prescribed medications. N o subject had taken sleeping medication m o r e t h a n five times, suggesting that medication use was not yet chronic. Professional help for sleeping problems had been sought by only 3.1 07o o f those with disturbed sleep.
383
Sleep Disturbance in Adolescents DISCUSSION
A significant number of adolescents experience sleeping difficulties, some of considerable severity and duration. While some of these problems may be transient and associated with developmental crises or life events, this study found that over half of the young adolescents who reported difficulty sleeping had had the problem for a year or more. The ways in which adolescents learn to deal with sleep disturbance may set the pattern for how they deal with it later in life. While medication and alcohol use were not common remedies among the adolescents studied (about one in six), and at least half of those who reported using medication had used aspirin, the tendency to rely on a quick chemical solution may persevere. Intervention may be appropriate regardless of the duration or transience of the problem. Similar to the results of other studies of adolescent sleep disturbance, this study found few differences in the sleep habits, environment, or beliefs of good and poor sleepers. As a group these adolescents showed relatively poor sleep hygiene and held several misconceptions about sleep. There was some evidence that poor sleepers may be more affected by basic sleep hygiene than normal sleepers. For example, both good and poor sleepers went to bed and arose later on weekends than weekdays. Similar patterns have been found in studies of 10- to 13-year-old children (Anders et al., 1978). The average shift in bedtime of 102 min found in this study of 13-17 year olds was considerably more than the 65-min shift found by Anders and his associates, supporting their Suggestion that bedtime may get progressively later on weekends due to social pressures as a child gets older. This study also found that the majority of subjects, regardless of sleep status, reported feeling tired in the morning, a feeling that may be associated with the hormonal changes of adolescence (Carskadon, 1979). However, while fewer good sleepers reported feeling tired in the afternoon and more reported feeling tired in the evening, most poor sleepers reported being most awake in the evening. These findings support the hypothesis offered by Anders and his colleagues that at least some adolescents who experience chronically disturbed sleep may have dysrhythms of the sleep-wake cycle, or delayed sleep-phase syndrome (Anders et al., 1980). These subjects may be more phase shifted from weekend to weekdays than other sleepers, as there was a significant trend in the data in this direction, or they may be less adaptable to changes in the sleep-wake cycle from weekday to weekend than good sleepers. Good sleep hygiene emphasizing stable bedtimes and waketimes may be critical for this group of poor sleepers. This study also found that poor sleepers exhibited more cognitive and behavioral signs of daytime stress than good sleepers. While the causal rela-
384
KirmiI-Gray, Eagleston, Gibson, and Thoresen
tionships between d a y t i m e stress a n d sleeping p r o b l e m s are unclear, the association between these two p r o b l e m s suggests that b o t h m a y be i m p a c t e d s i m u l t a n e o u s l y in a n i n t e r v e n t i o n (cf. K i r m i l - G r a y e t al., 1984; T h o r e s e n a n d Kirmil-Gray, 1984). Very few subjects in this study sought help for their sleep, even t h o u g h some considered their p r o b l e m s to be severe or very severe. Int e r v e n t i o n s designed to help adolescents reduce d a y t i m e stress m a y be m o r e socially acceptable t h a n treatments for sleep disturbance a n d m a y reduce stress as well as i m p r o v e sleep.
REFERENCES Anders, T. F., Carskadon, M., Dement, W., and Harvey, K. (1978). Sleep habits of children and the identification of pathologically sleepy children. Child Psychiat. Hum. Dev. 9(1): 57-63. Anders, T., Carskadon, M., and Dement, W. (1980). Sleepand sleepinessin children and adolescents. Pediat. Clin. No. Am. 27(4): 29-43. Bertelson, A., and Monroe, L. J. (1979). Personality patterns of adolescent poor and good sleepers. J. Abnorm. Child Psychol. 7(2): 191-197. Bixler, W. O., Kales, A., Soldatos, C. R., Kales, D., and Healey, S. (1979). Prevalence of sleep disorders in the Los Angeles Metropolitan. Am. J. Psychiat. 136(10): 1257-1262. Carskadon, M. (1979). Determinants o f Daytime Sleepiness, Adolescent Development, Extended and Restricted Sleep, Ph.D. thesis, Stanford University, Stanford, Calif. Carskadon, M., Dement, W., Mitler, M. M., Guilleminault, C., Zarcone, V. P., and Spiegel, R. (1976). Self-reports versus sleep laboratory findings in 122 drug-free subjects with complaints of chronic insomnia. Am. J. Psychiat. 133: 1382-1388. Hauri, P., and Sobel, R. (1977). Sleep and sleep pathology in rural 19-year-olds.Sleep Res. 6. Hauri, P., Percy, L., Olmstead, E., and Sateia, M. (1980). Childhood onset insomnia. Sleep Res. 9: 201. Karacan, I., Thornby, I., Anch, M., Holzer, C., Warheit, G., Schwab, J., and Williams, R. (1976). Prevalenceof sleep disturbance in a primary urban Florida county. Soc. Sci. Med. 10: 239-244. Kirmil-Gray, K., Eagleston, J. R., Thoresen, C. E., and Zarcone, V. P. (1985). Brief consultation and stress management treatments for drug-dependent insomnia: Effects on sleep quality, self-efficacy, and daytime stress. J. Behav. Med. 8: 79-99. Korlath, J., Baizerman, M., and Williams, S. (1976). Twin city adolescent health attitudes, knowledge, and behavior. Center Q. Focus 1-6. Marks, P. A., and Monroe, L. J. (1976). Correlates of adolescent poor sleepers. J. Abnorm. Psychol. 83: 243-246. Price, V. A., Coates, T. J., Thoresen, C. E., and Olmstead, O. A. (1978). Prevalence and correlates of poor sleep among adolescents. Am. J. Dis. Child. 132: 583-586. Thoresen, C. E., and Kirmil-Gray, K. (in press). Behavioral treatment of insomnia. In Mazur, F. (ed.), Psychological Techniques in Primary Care: A Problem Management Handbook f o r the Health Professional, Plenum, New York. White, L., Hahn, P. M., and Mitler, M. M. (1980). Sleep questionnaire in adolescents. Sleep Res. 9: 100.
Sleep Disturbance in Adolescents: Sleep Quality, Sleep Habits, Beliefs About Sleep, and Daytime Functioning Kathleen KirmiI-Gray,~ Jean R. Eagleston, Elizabeth G i b s o n , and Carl E. Thoresen 2 Received July 2, 1984; accepted for publication July 25, 1984
This study examined the prevalence and correlates o f sleep disturbance in adolescents. Two hundred seventy-seven 9th- and lOth-grade students completed a questionnaire on sleep quality, sleep habits, beliefs about sleep, and daytime mood and functioning. Based on their responses, subjects were classified as good sleepers (66%), occasional poor sleepers (23%), and chronic poor sleepers (11%). Occasional and chronic poor sleepers reported being significantly more depressed, without energy, tense, moody, and irritable and less rested and alert than good sleepers. They were also more likely to describe themselves negatively. However, poor sleepers were not consistently more tired than good sleepers. Rather, they tended to be least tired in the evening, the time when most good sleepers reported feeling tired. There weref e w differences in the sleep habits and beliefs about sleep o f good and poor sleepers. All subjects reported shifts in bedtimes and waketimes from weekdays to weekends, with occasional and chronic poor sleepers showing a tendency toward greater shifts, a possible factor contributing to their sleep disturbance. Occasional and chronic poor sleepers also reported more observable behaviors and feelings o f stress than good sleepers. The need for early intervention with particular attention to teaching adolescents about good sleep habits and the need f o r stable bedtimes and waketimes and the possibility of joint intervention on daytime stress and sleeping problems are discussed. This research was supported by NIMH Grant MH27551. We gratefully acknowledge Kristen Thoresen and Daytime Stress and Sleep Project staff for their help in conducting this study. We also thank Mary Carskadon for her comments and suggestions on the manuscript. ~Research Associate, Center for Educational Research, Stanford University, Stanford, California. Received her Ph.D. from Stanford University and is currently Director of the Health in Youth Project, a study of chronic stress and Type A behavior in children and
adolescents. ZTo whom correspondence should be addressed at School of Education, Stanford University, Stanford, California 94305. 375 0047-2891/84/1000-0375503.50/0 © 1984 Plenum Publishing Corporation
376
KirmiI-Gray, Eagleston, Gibson, and Thoresen
INTRODUCTION Between 15 and 50°70 of adolescents report at least occasional difficulty falling asleep or staying asleep, with 7-13°70 of this age group experiencing chronic and severe insomnia (Price et al., 1978; Korlath et al., 1976; Karacan et al., 1976; Hauri and Sobel, 1977; White et aft, 1980). Although few adolescents seek help for sleeping problems, the prevalance of disturbed sleep among youth is of some concern because retrospective studies and clinical anecdotes of adult insomniacs suggest that insomnia often begins early in life and persists into adulthood. Hauri and his colleagues (Hauri et al., 1980) found that 47070 of adult insomniacs reported their sleeping difficulties to have begun in childhood or adolescence, while Bixler and his associates (Bixler et al., 1979) calculated that 18070 of their sample experienced significant difficulty sleeping before the age of 20 years. The possibility of early intervention when sleeping problems may be less severe and more amenable to change has led a few investigators to study the correlates of sleep disturbance in adolescence (Price et al., 1978; Marks and Monroe, 1976; Bertelson and Monroe, 1979; Hauri and Sobel, 1977). Price and her colleagues examined the sleep habits, daytime feelings, and self-perceptions of 627 normal high-school students. They found few differences in the sleep habits or nighttime routines of good and poor sleepers but marked differences in their daytime experience. Poor sleepers reported being more tired, depressed, tense, moody, and irritable than good sleepers, with those complaining of chronic and severe insomnia showing the greatest frequency of daytime disturbance. Poor sleepers also tended to describe themselves more negatively. In a study of 394 normal 19 year olds, Hauri and Sobel (1977) found teenage insomnia to be related to anger, depression, school adjustments, and life stress. The present study was designed (I) to replicate partially the findings of other investigators regarding the sleep habits, feelings, and self-perceptions of normal adolescents with sleeping problems, (2) to investigate the beliefs and misconceptions that adolescents hold about sleep, and (3) to examine the relationship between chronic stress and sleep disturbance in adolescents.
METHOD
Subjects were 277 students in the 9th and 10th grades enrolled in required health classes in three senior high schools in the San Francisco Bay Area. They were told that researchers at Stanford University were interested in learning about the stress and sleep patterns of young people and were asked
Sleep Disturbance in Adolescents
377
to fill out a questionnaire during their regular class period. Approximately equal numbers of girls and boys participated in the study (girls, N = 146; boys, N = 130). They ranged in age from 13 to 17 years, with a mean age of 15 years; 65% were freshmen, and 35°7o sophomores. The questionnaire assessed perceived sleep quality, sleep habits and environment, beliefs about sleep, and daytime mood and functioning. Subjects who reported disturbed sleep were asked to complete an additional section on the management of their sleeping problem.
RESULTS Prevalence of Disturbed Sleep Students were divided into three groups on the basis of their responses to questions about sleep quality. Group 1, chronic poor sleepers (30 students; 11%), reported at least one of the following problems 3 or more nights per week: (I) taking 45 rain or longer to fall asleep, (2) awakening three or more times per night, and (3) staying awake during the night for 30 min or more. These criteria have been used to discriminate good and poor sleepers and thus allow comparisons between the results of this study and those of other studies (Price et al., 1978; Carskadon et al., 1976). Group 2, occasional poor sleepers (63 students; 23%), reported some sleeping difficulties but did not meet the criteria of the chronic poor sleepers. Group 3, good sleepers (184 students; 66%), reported no sleeping problems. Differences between groups were assessed by chi-square analyses and one-way analysis of variance as appropriate. Table I presents data on the prevalence of sleep disturbance among these young adolescents. Similar to other studies of both adolescents and adults, significantly more girls (41%) than boys (25%) reported sleeping difficulties (p < 0.02), with the greatest sex differences found among occasional poor sleepers. Chronic poor sleepers reported more severe and more frequent sleep disturbance of all types. Problems falling asleep were most common. However, even at their young age, a notable percentage of occasional (25%) and chronic poor (37%) sleepers complained of difficulties maintaining sleep. Chronic poor sleepers reported significantly shorter total sleep times than either occasional poor or good sleepers. Most occasional (52.6%) and chronic poor sleepers (62.1%) had problems sleeping for a year or more, and some considered their problem severe or very severe (1.7, 17.9%).
378
KirmiI-Gray, Eagleston, Gibson, and Thoresen Table 1. Prevalence and Description o f Sleep Disturbance A m o n g Y o u n g Adolescents Percentage
Characteristics Males Females Difficulty falling asleep 3 or m o r e n i g h t s / w e e k 45 m i n or m o r e Difficulty staying asleep 3 or more nights/week 3 or more awakenings A w a k e 30 m i n or m o r e D u r a t i o n of sleeping p r o b l e m > 1 year Severity Severe or very severe T o t a l h o u r s slept
Good sleepers ( N = 184)
Occasional poor sleepers ( N = 63)
Chronic poor sleepers ( N = 30)
74.6 58.9 0 --0 -
16.2 28.8 63.5 18.0 33.3 25.4 4.8 9.5 19.0
9.2 12.3 93.3 90.0 80.0 36.7 20.0 13.3 20.0
-
52.6
62.1
1.7 7.9
17.9 7.0
7.8
Daytime Feelings and Mood Significant differences in the daytime feelings and mood of good and poor sleepers are reported in Table II. Occasional and chronic poor sleepers reported feeling more depressed, tense, without energy, moody, irritable, less rested, and less alert than good sleepers. They were also more likely to use negative adjectives to describe themselves, suggesting a negative self-image. Interestingly, poor sleepers were not consistently more tired during the day than good sleepers. There were no significant differences between groups in the percentage of students feeling tired in the morning; most subjects reported feeling tired in the morning. However, more occasional and chronic poor sleepers reported feeling tired during the afternoon, a trend that reversed itself in the evening, when fewer chronic poor sleepers reported feeling tired than occasional or good sleepers. When asked if they considered themselves "a night person," more occasional and chronic poor sleepers responded positively, although the differences were not significant statistically (52.0, 61.9, and 69.0%).
Sleep Habits and Environment There were few differences in the sleep habits or sleep environments of good and poor sleepers. Reading, watching television, studying, and listening to music in bed and taking naps were no more common to poor sleepers
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379
Table !1. Daytime Feelings of Good, Occasional Poor, and Chronic Poor Sleepers Percentage
Tired in morning Tired in afternoon Tired in evening Depressed Without energy Tense Moody Irritable Rested Alert Negative personal description
Good sleepers (N = 184)
Occasional poor sleepers (N = 63)
Chronic poor sleepers (N = 30)
X2
78.8 41,5 53.1 36,0 35.1 37.3 23.4 6.5 50.0 47,3 3.6
85.7 65.0 56.7 66.7 49.2 53.3 36.5 9.5 23.8 28.6 t0.2
90.0 72.4 30.0 66.7 53.3 53.3 43.3 23,3 20.0 26.7 24.1
NS 16.3a 6.4* 22.3 a 6.0* 6.2* 7.6* 8.94 19.4 a 9.6 b 35.9 ~
°p < 0.05.
~p < 0.01. ~p < 0.001. ap < 0.0001.
than good sleepers. Occasional and chronic poor sleepers did report drinking more caffeinated beverages per day than good sleepers (I .2, 1.7, and 1.8 cups; p < 0.05) and eating in bed 1 or more nights per week (20, 36, and 45°/0; p < 0.01). Chronic poor sleepers were also more likely to complain of a moderate or noisy sleep environment (47%0) than either occasional poor (22%) or good (20°70) sleepers. Interestingly, physical problems such as allergies that might be expected to interfere with sleep as well as recurrent dreams and nightmares were most common among occasional poor sleepers [physical problems-20.7, 41.3, and 31.0°-/o (p < 0.01); recurrent dreams-6.1, 17.7, and 13.3% (p < 0.02); nightmares-1.7, 8.1, and 0.0% (p < 0.02)]. Both occasional and chronic poor sleepers were more likely than good sleepers to experience crawling sensations in their legs and leg jerks, suggesting the possibility of physiological causes such as nocturnal myocionus and restless leg syndrome for sleep disturbance [crawling sensations- 1.1, 6.5, and 6.707o (p < 0.04); leg jerks-7.3, 16.1, and 16.7°70 (t9 < 0.07)]. All subjects reported significant shifts in bedtimes, waketimes, and total sleep time from weekdays to weekends. They tended to go to bed 1.7 hr later (p < 0.001) and get up 2.7 hr later (17 < 0.001) on weekends than weekdays, thus increasing their total sleep time on weekends by 1 hr. Figure 1 displays the significant linear trend in bedtime and waketime shifts found. Chronic poor sleepers showed the greatest shifts, occasional poor sleepers the next greatest shifts, and good sleepers the smallest shifts [bedtime s h i f t - 1.6, 1.9, and 2.1 hr (p < 0.05); waketime shift-2.6, 2.9, and 3.1 hr (17 < 0.03)]. However, differences between groups were not significant.
380
KirmiI-Gray, Eagleston, Gibson, and Thoresen 4 hours
Waketime shifts
3 hours
Bedtln~ shifts
f ~
2 hours
J | hour
Good
Sleepers
Occasional
Poor Sleepers
Chronic Poor
Sleepers
Fig. 1. Shifts in bedtimes and waketimes from weekdays to weekendsof good, occasional poor, and chronic poor sleepers.
Beliefs A b o u t Sleep
To explore the relationship between beliefs about sleep and sleep disturbance, subjects were asked if they agreed or disagreed with several statements about sleep. Subjects as a group held several misconceptions about sleep and daytime feelings. Most of these misconceptions related to the relationship between nighttime sleep and daytime functioning and the possibility of making up or storing up sleep. People need at least 8 hours of sleep. (Agreement = 61%.) Without enough sleep, you will not function well during the day. (96%) If you feel tired during the day, you must not have slept well the night before. (48070) If you don't get enough sleep on a particular night, you have to make it up at another time. (40°70) If you know you won't be getting enough sleep, you can prepare by sleeping more hours on preceding nights. (50%) Only four beliefs discriminated significantly between groups as shown in Table III. Occasional poor sleepers were less aware than good or chronic poor sleepers that the number of hours people need to sleep varies from person to person but were more aware of the dangers of sleeping pills. Both
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381
Table !!!. Beliefs A b o u t Sleep That Differentiate Good, Occasional Poor, and Chronic Poor Sleepers Percentage
People have an individual a m o u n t of sleep they need to feel rested. (True) Most sleeping pills are harmless. (False) Changes in noise, light, or surroundings will interfere with sleep. (True) I ought to be able to sleep welt regardless o f what is going on in my life. (False)
Good sleepers (N = 184)
Occasional poor sleepers (N = 63)
Chronic poor sleepers (N = 30)
X~
95.1
85.7
96.7
7.1 *
23.0
9.8
25.1
5.2 a
68.5
82.5
86.7
7.7 ~
41.0
20.6
26.7
9.5 b
"p < 0.05. bp < 0.0I.
groups of poor sleepers were aware that changes in the environment could affect sleep and were less likely to feel that they should sleep well regardless of what was going on in their lives.
Daytime Stress and Sleep Disturbance Significant differences in the daytime stress of good and poor sleepers are reported in Table IV. All individual items, as well as the total score, showed a significant linear trend, with chronic poor sleepers generally reporting the most signs of daytime stress, occasional poor sleepers the next most, and good sleepers the least. Poor sleepers reported more observable signs and feelings of stress and spent more time worrying, thinking about two things at once, and thinking about something else when talking with someone than good sleepers. They also tended to be more emotionally labile, to think more negative thoughts, and to hold more beliefs that might be expected to cause stress (for example, "I often struggle to prove myself" or "I often feel dissatisfied with how well I am doing"). Sleep-disturbed subjects were also more likely to report displaying characteristics of the Type A behavior pattern.
Management of Sleeping Problems Of occasional and chronic poor sleepers, nearly 60°/0 believed that the quality of their day affected the way they slept at night. Having a good day
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KirmiI-Gray, Eagleston, Gibson, and Thoresen
Table IV. Self-Reported Daytime Stress of Good, Occasional Poor, and Chronic Poor Sleepers
Observable signs of stress* Feelings of stress Emotional lability Stress-producing beliefs
Good sleepers (N = 184)
Occasional poor sleepers (N-- 63)
Chronic poor sleepers (N = 30)
F
1.2 3.2 2.9 4.6
2.8 5.5 4.2 6.5
2.2 5.2 4.2 7.5
12.0a 13.5" 11.I" 13.6~
6.3
7.1
7.2
2.5c
5.3
5.9
6.5
3.6c
Does two or more things at onceb Thinks about other things when someone is talking Engages in negative thoughts about self Worries about getting everything done Considers oneself Type A
6.4
7.1
8.3
6.8~
6.4 5.7
6.8 6.7
7.8 6.2
3.9c 3.9"
Total daytime stress score
16.4
23.8
24.1
21.1"
"Frequency. bRatings on a 12-point scale from almost never (1) to almost always (12). Cp < 0.05. dp < 0.01.
~p < 0.001.
or exercising was t h o u g h t to lead to a g o o d night's sleep, while having m u c h on their minds or having had an a r g u m e n t were reported to result in disturbed sleep. Most subjects (62.707o) also believed that how well they slept influenced their functioning the next day; p o o r sleep was associated with feeling tired, irritable, m o o d y , and lazy. A variety o f remedies was used to m a n a g e sleeping problems including listening to the radio (85070), reading (75.3070), focusing t h o u g h t s on something specific (69.6070), watching television, (52.6070), and relaxing systematically (52.907o). All were reported to w o r k at least sometimes. Subjects were less inclined to use medication or alcohol to help themselves sleep, a l t h o u g h 14.9070 o f those with disturbed sleep had used medication at least once, and 16.4070 had used alcohol, with 907o reporting use o f both. Medication and alcohol use did not covary with the severity o f sleep disturbance. H a l f o f the subjects w h o reported having taken medication had used aspirin, while the other half h a d used either over-the-counter or prescribed medications. N o subject had taken sleeping medication m o r e t h a n five times, suggesting that medication use was not yet chronic. Professional help for sleeping problems had been sought by only 3.1 07o o f those with disturbed sleep.
383
Sleep Disturbance in Adolescents DISCUSSION
A significant number of adolescents experience sleeping difficulties, some of considerable severity and duration. While some of these problems may be transient and associated with developmental crises or life events, this study found that over half of the young adolescents who reported difficulty sleeping had had the problem for a year or more. The ways in which adolescents learn to deal with sleep disturbance may set the pattern for how they deal with it later in life. While medication and alcohol use were not common remedies among the adolescents studied (about one in six), and at least half of those who reported using medication had used aspirin, the tendency to rely on a quick chemical solution may persevere. Intervention may be appropriate regardless of the duration or transience of the problem. Similar to the results of other studies of adolescent sleep disturbance, this study found few differences in the sleep habits, environment, or beliefs of good and poor sleepers. As a group these adolescents showed relatively poor sleep hygiene and held several misconceptions about sleep. There was some evidence that poor sleepers may be more affected by basic sleep hygiene than normal sleepers. For example, both good and poor sleepers went to bed and arose later on weekends than weekdays. Similar patterns have been found in studies of 10- to 13-year-old children (Anders et al., 1978). The average shift in bedtime of 102 min found in this study of 13-17 year olds was considerably more than the 65-min shift found by Anders and his associates, supporting their Suggestion that bedtime may get progressively later on weekends due to social pressures as a child gets older. This study also found that the majority of subjects, regardless of sleep status, reported feeling tired in the morning, a feeling that may be associated with the hormonal changes of adolescence (Carskadon, 1979). However, while fewer good sleepers reported feeling tired in the afternoon and more reported feeling tired in the evening, most poor sleepers reported being most awake in the evening. These findings support the hypothesis offered by Anders and his colleagues that at least some adolescents who experience chronically disturbed sleep may have dysrhythms of the sleep-wake cycle, or delayed sleep-phase syndrome (Anders et al., 1980). These subjects may be more phase shifted from weekend to weekdays than other sleepers, as there was a significant trend in the data in this direction, or they may be less adaptable to changes in the sleep-wake cycle from weekday to weekend than good sleepers. Good sleep hygiene emphasizing stable bedtimes and waketimes may be critical for this group of poor sleepers. This study also found that poor sleepers exhibited more cognitive and behavioral signs of daytime stress than good sleepers. While the causal rela-
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KirmiI-Gray, Eagleston, Gibson, and Thoresen
tionships between d a y t i m e stress a n d sleeping p r o b l e m s are unclear, the association between these two p r o b l e m s suggests that b o t h m a y be i m p a c t e d s i m u l t a n e o u s l y in a n i n t e r v e n t i o n (cf. K i r m i l - G r a y e t al., 1984; T h o r e s e n a n d Kirmil-Gray, 1984). Very few subjects in this study sought help for their sleep, even t h o u g h some considered their p r o b l e m s to be severe or very severe. Int e r v e n t i o n s designed to help adolescents reduce d a y t i m e stress m a y be m o r e socially acceptable t h a n treatments for sleep disturbance a n d m a y reduce stress as well as i m p r o v e sleep.
REFERENCES Anders, T. F., Carskadon, M., Dement, W., and Harvey, K. (1978). Sleep habits of children and the identification of pathologically sleepy children. Child Psychiat. Hum. Dev. 9(1): 57-63. Anders, T., Carskadon, M., and Dement, W. (1980). Sleepand sleepinessin children and adolescents. Pediat. Clin. No. Am. 27(4): 29-43. Bertelson, A., and Monroe, L. J. (1979). Personality patterns of adolescent poor and good sleepers. J. Abnorm. Child Psychol. 7(2): 191-197. Bixler, W. O., Kales, A., Soldatos, C. R., Kales, D., and Healey, S. (1979). Prevalence of sleep disorders in the Los Angeles Metropolitan. Am. J. Psychiat. 136(10): 1257-1262. Carskadon, M. (1979). Determinants o f Daytime Sleepiness, Adolescent Development, Extended and Restricted Sleep, Ph.D. thesis, Stanford University, Stanford, Calif. Carskadon, M., Dement, W., Mitler, M. M., Guilleminault, C., Zarcone, V. P., and Spiegel, R. (1976). Self-reports versus sleep laboratory findings in 122 drug-free subjects with complaints of chronic insomnia. Am. J. Psychiat. 133: 1382-1388. Hauri, P., and Sobel, R. (1977). Sleep and sleep pathology in rural 19-year-olds.Sleep Res. 6. Hauri, P., Percy, L., Olmstead, E., and Sateia, M. (1980). Childhood onset insomnia. Sleep Res. 9: 201. Karacan, I., Thornby, I., Anch, M., Holzer, C., Warheit, G., Schwab, J., and Williams, R. (1976). Prevalenceof sleep disturbance in a primary urban Florida county. Soc. Sci. Med. 10: 239-244. Kirmil-Gray, K., Eagleston, J. R., Thoresen, C. E., and Zarcone, V. P. (1985). Brief consultation and stress management treatments for drug-dependent insomnia: Effects on sleep quality, self-efficacy, and daytime stress. J. Behav. Med. 8: 79-99. Korlath, J., Baizerman, M., and Williams, S. (1976). Twin city adolescent health attitudes, knowledge, and behavior. Center Q. Focus 1-6. Marks, P. A., and Monroe, L. J. (1976). Correlates of adolescent poor sleepers. J. Abnorm. Psychol. 83: 243-246. Price, V. A., Coates, T. J., Thoresen, C. E., and Olmstead, O. A. (1978). Prevalence and correlates of poor sleep among adolescents. Am. J. Dis. Child. 132: 583-586. Thoresen, C. E., and Kirmil-Gray, K. (in press). Behavioral treatment of insomnia. In Mazur, F. (ed.), Psychological Techniques in Primary Care: A Problem Management Handbook f o r the Health Professional, Plenum, New York. White, L., Hahn, P. M., and Mitler, M. M. (1980). Sleep questionnaire in adolescents. Sleep Res. 9: 100.
