Sleep Disturbances and Common Mental Disorders in College Students Kia L. Byrd, BS Bizu Gelaye, PhD, MPH Mahlet G. Tadesse, ScD Michelle A. Williams, ScD Seblewengel Lemma, MPH Yemane Berhane, MD, MPH, PhD Objective: We attempted to estimate the prevalence of common mental disorders (CMDs) and examine the association of sleep disorders with presence of CMDs. Methods: A self-administered questionnaire was used to ascertain demographic information and behavioral characteristics among 2645 undergraduate students in Ethiopia. Standard questionnaires were used to assess CMDs, evening chronotype, sleep quality, and daytime sleepiness. Results: A total of 716 students (26.6%) were characterized as having CMDs. Women had higher prevalence of CMDs (30.6%) compared to men (25.4%). After adjusting for potential confounders, daytime sleepiness (OR = 2.02; 95% CI 1.64-2.49) and poor sleep quality (OR = 2.36; 95% CI 1.91-2.93) were associated with increased odds of CMDs. Conclusion: There is a high prevalence of CMDs comorbid with sleep disorders among college students. Key words: Africa, college, Ethiopia, mental disorders, sleep Health Behavior & Policy Review. 2014;1(3):229-237 DOI: http://dx.doi.org/10.14485/HBPR.1.3.7
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leep is an essential physiological function regulated by both circadian rhythms and sleepwake homeostatic systems that determine duration and timing.1 Circadian rhythms, the physical, mental, and behavioral fluctuations during a 24-hour period, reportedly influence sleep quality and daytime sleepiness in adolescents.2 Circadian rhythms include individual preferences for morningness and eveningness (ME), a set of chronotypes indicating preference for physical and mental activities during a specific time of the day.3 A number of studies have demonstrated that evening types are more likely to experience circadian rhythm alterations, other sleep disorders, mood disturbances, suicidal behavior, and substance use.4-6 People who experience irregular sleep patterns and poor sleep quality have reported increased lev-
els of daytime sleepiness.7 College students are particularly susceptible to patterns of sleep disturbance and poor sleep quality due to increased physiologic changes, academic workload and psychosocial concerns.8,9 Behavioral characteristics, such as alcoholic beverage consumption, substance use, and stimulant drink consumption also have been shown to increase the odds of excessive daytime sleepiness and various mental health disorders.10 An accumulating body of epidemiologic literature documents that mental health disorders among sub-Saharan Africans are the leading causes of morbidity and premature mortality.11 A survey conducted in Ethiopia showed a high prevalence of common mental disorders among adults.11 Furthermore, mental disorders were shown to account for 11% of the total burden of diseases in Ethiopia.12
Kia L. Byrd, Research Fellow, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, MA; Bizu Gelaye, Research Scientist, Department of Epidemiology, Harvard School of Public Health, Boston, MA; Mahlet G. Tadesse, Associate Professor, Department of Mathematics & Statistics, Georgetown University, Washington, DC; Michelle A. Williams, Professor and Chair, Department of Epidemiology, Harvard School of Public Health, Boston, MA; Seblewengel Lemma, Public Health Expert and Yemane Berhane, Professor and Director, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia. Correspondence Dr Gelaye; [email protected]
Health Behavior & Policy Review. 2014;1(3):229-237
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Sleep Disturbances and Common Mental Disorders in College Students
Common mental disorders (CMDs), defined usually by depression, anxiety, and somatoform disorders, are now recognized as important public health problems in low- and middle-income countries (LMICs). They particularly impact young adults because the incidence of diagnosed mental health disorders tend to peak during early adulthood.13 Documented relationships between shortened sleep and excessive drowsiness, tension, and poor mood have been reported in university students and other young adult populations in several developed countries.14 Gau et al15 reported that evening type individuals in Taiwan had higher frequencies of trouble sleeping, more frequent daytime napping, and greater tendencies for social withdrawal.15 Little is known about the relationship between sleep disorders and CMDs among young adults, particularly among sub-Saharan Africans. In the present study, we examined the extent to which biological chronotype, sleep quality, and daytime sleepiness are associated with presence of CMDs among Ethiopian college students. We expect that the findings of this study will provide a more thorough and comprehensive understanding of circadian rhythm preferences and sleep patterns as risk factors of mental health in LMICs. METHODS Study Setting and Sample A cross-sectional survey was conducted at the Universities of Gondar and Haramaya, Ethiopia. The study procedures have been described in detail elsewhere.16 Briefly, a multistage sampling design by means of probability proportional to size (PPS) was used to select departments and all students from those departments were invited to participate. Students who expressed an interest in participating in the study were invited to meet in a large classroom or an auditorium where they were informed about the purpose of the study and asked to participate in the survey. There was no set time limit for completing the survey. Students who could not read the survey (ie, were blind) were excluded, as were students enrolled in correspondence, extension, or night school program. A total of 2817 undergraduate students consented and participated in the study. For this study, after excluding participants with incomplete questionnaires on sleep disorders, the final analyzed sample consisted of 2645 students. Based on the information provided,
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students excluded from analysis had similar characteristics as those considered for analysis. Data Collection and Variables A self-administered questionnaire was used for data collection. The questionnaire ascertained demographic information including age, sex, and education level. Questions regarding behavioral risk factors such as caffeinated beverages, tobacco, alcohol, and Khat (Catha edulis Forsk) - psycho-stimulant substance grown in East Africa - consumption were also included. Participants’ anthropometric measurements were taken by nurse-researchers using standard protocols. Height and weight were measured without shoes or outerwear. Height was measured to the nearest 0.1 cm and weight was measured to the nearest 0.1 kg. All anthropometric values consisted of the mean of three measurements. General Health Questionnaire (GHQ-12). The 12-item version of the General Health Questionnaire (GHQ-12) was used to screen for non-pathological common mental disorders.17 The GHQ-12 has been used worldwide, including sub-Saharan Africa18 for studies of various clinical and non-clinical populations. The GHQ-12 asks respondents to report how they felt during last 4 weeks on a range of variables including problems with sleep and appetite, subjective experiences of stress, tension, or sadness, mastering of daily problems, decision making and self-esteem. Response choices included: less than usual, no more than usual, more than usual and much more than usual. Scoring was 0 for the first 2 choices and 1 for the next 2. The maximum possible score was 12 with higher scores suggesting higher mental distress. Presence of CMDs was defined for this study using previously established cut off points in other study populations. Students who scored ≥5 on the GHQ12 scale were considered as having CMDs.19,20 Morningness-Eveningness Questionnaire (MEQ). Morningness/eveningness chronotype were assessed using the Horne and Ostberg MEQ.21 The MEQ21 is a 19-item questionnaire that identifies morningness-eveningness preference. The scores range from 16 to 86 and participants can be classified in 5 categories: definite and moderate E-type, neutral type, and moderate and definite M-type. Higher values on MEQ indicate stronger morningness preference. For this study we used the following cut offs: (1) 16 to 30 for evening; (2) 31 to 41
Byrd et al
for moderate evening; (3) 42 to 58 for intermediate; (4) 59 to 69 for moderate morning, and (5) 70 to 86 for morning. Pittsburgh Sleep Quality Index (PSQI). Sleep quality was assessed using the previously validated Pittsburgh Sleep Quality Index (PSQI).22 The PSQI has been validated among college students in sub-Saharan Africa.23 The PSQI is a 19-item selfreported questionnaire that evaluates sleep quality over the past month. It has seven sleep components including duration of sleep, sleep disturbance, sleep latency, habitual sleep efficiency, use of sleep medicine, daytime dysfunction, and overall sleep quality. Each sleep component yields a score ranging from 0 to 3, with 3 indicating the greatest dysfunction.22 The sleep component scores are summed to yield a total score ranging from 0 to 21 with higher total scores (referred to as global scores) indicating poor sleep quality. On the basis of prior studies,22 participants with a global score of >5 were classified as poor sleepers. Those students with a score ≤5 were classified as good sleepers. Epworth Sleep Scale (ESS).The ESS is a measure of individual’s general level of daytime sleepiness.24 It is an 8-item questionnaire capturing an individual’s propensity to fall asleep during commonly encountered situations on a scale from 0 to 3. The scores for the 8 questions are added together to obtain a single total score ranging from 0 to 24. In adults, an ESS score ≥10 is taken to indicate increased daytime sleepiness.24 The ESS has been used globally in different study populations including college students in Southeast Asia and adults in sub-Saharan Africa.25,26
Statistical Analysis We examined frequency distributions of demographic and lifestyle characteristics. Characteristics of those participants with and without CMDs were compared using Student’s t tests, Wilcoxon’s rank-sum tests, or chi-square tests. Sex-specific prevalence of CMDs and 95% confidence intervals (95% CI) across age groups were also estimated.29 Spearman correlation coefficients were calculated to assess associations of sleep quality and daytime sleepiness (based on total PSQI and ESS scores, respectively) with total GHQ score. Logistic regression models were used to estimate odds ratios (OR) 95% CI for the association of sleep disorders (evening chronotype, poor sleep quality and daytime sleepiness) with CMDs. The distribution of PSQI scores among students characterized as having CMDs and those students without CMDs was determined. All analyses were performed using SPSS Statistical Software (IBM SPSS Version 21, Chicago, IL, USA). All reported p-values are 2-tailed and deemed statistically significant at α = .05.
Other Covariates Body mass index (BMI) was calculated as weight (kg)/height squared (m2). BMI thresholds were set according to the World Health Organization (WHO) protocol (underweight:
S
leep is an essential physiological function regulated by both circadian rhythms and sleepwake homeostatic systems that determine duration and timing.1 Circadian rhythms, the physical, mental, and behavioral fluctuations during a 24-hour period, reportedly influence sleep quality and daytime sleepiness in adolescents.2 Circadian rhythms include individual preferences for morningness and eveningness (ME), a set of chronotypes indicating preference for physical and mental activities during a specific time of the day.3 A number of studies have demonstrated that evening types are more likely to experience circadian rhythm alterations, other sleep disorders, mood disturbances, suicidal behavior, and substance use.4-6 People who experience irregular sleep patterns and poor sleep quality have reported increased lev-
els of daytime sleepiness.7 College students are particularly susceptible to patterns of sleep disturbance and poor sleep quality due to increased physiologic changes, academic workload and psychosocial concerns.8,9 Behavioral characteristics, such as alcoholic beverage consumption, substance use, and stimulant drink consumption also have been shown to increase the odds of excessive daytime sleepiness and various mental health disorders.10 An accumulating body of epidemiologic literature documents that mental health disorders among sub-Saharan Africans are the leading causes of morbidity and premature mortality.11 A survey conducted in Ethiopia showed a high prevalence of common mental disorders among adults.11 Furthermore, mental disorders were shown to account for 11% of the total burden of diseases in Ethiopia.12
Kia L. Byrd, Research Fellow, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, MA; Bizu Gelaye, Research Scientist, Department of Epidemiology, Harvard School of Public Health, Boston, MA; Mahlet G. Tadesse, Associate Professor, Department of Mathematics & Statistics, Georgetown University, Washington, DC; Michelle A. Williams, Professor and Chair, Department of Epidemiology, Harvard School of Public Health, Boston, MA; Seblewengel Lemma, Public Health Expert and Yemane Berhane, Professor and Director, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia. Correspondence Dr Gelaye; [email protected]
Health Behavior & Policy Review. 2014;1(3):229-237
229
Sleep Disturbances and Common Mental Disorders in College Students
Common mental disorders (CMDs), defined usually by depression, anxiety, and somatoform disorders, are now recognized as important public health problems in low- and middle-income countries (LMICs). They particularly impact young adults because the incidence of diagnosed mental health disorders tend to peak during early adulthood.13 Documented relationships between shortened sleep and excessive drowsiness, tension, and poor mood have been reported in university students and other young adult populations in several developed countries.14 Gau et al15 reported that evening type individuals in Taiwan had higher frequencies of trouble sleeping, more frequent daytime napping, and greater tendencies for social withdrawal.15 Little is known about the relationship between sleep disorders and CMDs among young adults, particularly among sub-Saharan Africans. In the present study, we examined the extent to which biological chronotype, sleep quality, and daytime sleepiness are associated with presence of CMDs among Ethiopian college students. We expect that the findings of this study will provide a more thorough and comprehensive understanding of circadian rhythm preferences and sleep patterns as risk factors of mental health in LMICs. METHODS Study Setting and Sample A cross-sectional survey was conducted at the Universities of Gondar and Haramaya, Ethiopia. The study procedures have been described in detail elsewhere.16 Briefly, a multistage sampling design by means of probability proportional to size (PPS) was used to select departments and all students from those departments were invited to participate. Students who expressed an interest in participating in the study were invited to meet in a large classroom or an auditorium where they were informed about the purpose of the study and asked to participate in the survey. There was no set time limit for completing the survey. Students who could not read the survey (ie, were blind) were excluded, as were students enrolled in correspondence, extension, or night school program. A total of 2817 undergraduate students consented and participated in the study. For this study, after excluding participants with incomplete questionnaires on sleep disorders, the final analyzed sample consisted of 2645 students. Based on the information provided,
230
students excluded from analysis had similar characteristics as those considered for analysis. Data Collection and Variables A self-administered questionnaire was used for data collection. The questionnaire ascertained demographic information including age, sex, and education level. Questions regarding behavioral risk factors such as caffeinated beverages, tobacco, alcohol, and Khat (Catha edulis Forsk) - psycho-stimulant substance grown in East Africa - consumption were also included. Participants’ anthropometric measurements were taken by nurse-researchers using standard protocols. Height and weight were measured without shoes or outerwear. Height was measured to the nearest 0.1 cm and weight was measured to the nearest 0.1 kg. All anthropometric values consisted of the mean of three measurements. General Health Questionnaire (GHQ-12). The 12-item version of the General Health Questionnaire (GHQ-12) was used to screen for non-pathological common mental disorders.17 The GHQ-12 has been used worldwide, including sub-Saharan Africa18 for studies of various clinical and non-clinical populations. The GHQ-12 asks respondents to report how they felt during last 4 weeks on a range of variables including problems with sleep and appetite, subjective experiences of stress, tension, or sadness, mastering of daily problems, decision making and self-esteem. Response choices included: less than usual, no more than usual, more than usual and much more than usual. Scoring was 0 for the first 2 choices and 1 for the next 2. The maximum possible score was 12 with higher scores suggesting higher mental distress. Presence of CMDs was defined for this study using previously established cut off points in other study populations. Students who scored ≥5 on the GHQ12 scale were considered as having CMDs.19,20 Morningness-Eveningness Questionnaire (MEQ). Morningness/eveningness chronotype were assessed using the Horne and Ostberg MEQ.21 The MEQ21 is a 19-item questionnaire that identifies morningness-eveningness preference. The scores range from 16 to 86 and participants can be classified in 5 categories: definite and moderate E-type, neutral type, and moderate and definite M-type. Higher values on MEQ indicate stronger morningness preference. For this study we used the following cut offs: (1) 16 to 30 for evening; (2) 31 to 41
Byrd et al
for moderate evening; (3) 42 to 58 for intermediate; (4) 59 to 69 for moderate morning, and (5) 70 to 86 for morning. Pittsburgh Sleep Quality Index (PSQI). Sleep quality was assessed using the previously validated Pittsburgh Sleep Quality Index (PSQI).22 The PSQI has been validated among college students in sub-Saharan Africa.23 The PSQI is a 19-item selfreported questionnaire that evaluates sleep quality over the past month. It has seven sleep components including duration of sleep, sleep disturbance, sleep latency, habitual sleep efficiency, use of sleep medicine, daytime dysfunction, and overall sleep quality. Each sleep component yields a score ranging from 0 to 3, with 3 indicating the greatest dysfunction.22 The sleep component scores are summed to yield a total score ranging from 0 to 21 with higher total scores (referred to as global scores) indicating poor sleep quality. On the basis of prior studies,22 participants with a global score of >5 were classified as poor sleepers. Those students with a score ≤5 were classified as good sleepers. Epworth Sleep Scale (ESS).The ESS is a measure of individual’s general level of daytime sleepiness.24 It is an 8-item questionnaire capturing an individual’s propensity to fall asleep during commonly encountered situations on a scale from 0 to 3. The scores for the 8 questions are added together to obtain a single total score ranging from 0 to 24. In adults, an ESS score ≥10 is taken to indicate increased daytime sleepiness.24 The ESS has been used globally in different study populations including college students in Southeast Asia and adults in sub-Saharan Africa.25,26
Statistical Analysis We examined frequency distributions of demographic and lifestyle characteristics. Characteristics of those participants with and without CMDs were compared using Student’s t tests, Wilcoxon’s rank-sum tests, or chi-square tests. Sex-specific prevalence of CMDs and 95% confidence intervals (95% CI) across age groups were also estimated.29 Spearman correlation coefficients were calculated to assess associations of sleep quality and daytime sleepiness (based on total PSQI and ESS scores, respectively) with total GHQ score. Logistic regression models were used to estimate odds ratios (OR) 95% CI for the association of sleep disorders (evening chronotype, poor sleep quality and daytime sleepiness) with CMDs. The distribution of PSQI scores among students characterized as having CMDs and those students without CMDs was determined. All analyses were performed using SPSS Statistical Software (IBM SPSS Version 21, Chicago, IL, USA). All reported p-values are 2-tailed and deemed statistically significant at α = .05.
Other Covariates Body mass index (BMI) was calculated as weight (kg)/height squared (m2). BMI thresholds were set according to the World Health Organization (WHO) protocol (underweight:
