Daytime naps and depression risk: A meta-analysis of observational studies

Exploring artificial intelligence (AI) Chatbot usage behaviors and their association with mental health outcomes in Chinese university students

Technology dependence has long been a critical public health issue, especially among young people. With the development of AI chatbots, many individuals are integrating these tools into their daily lives. However, we have limited knowledge about the issues related to AI chatbot usage and dependence. Therefore, we conducted a cross-sectional survey to investigate AI chatbot usage behaviors and their association with mental health outcomes among Chinese university students. A total of 1004 students who met the inclusion criteria were included in the analysis. Our survey revealed that 45.8 % of students reported using AI chatbots in the last month, with most using them one to three days per week (78.5 %) and showing light (38.2 %) to moderate (37.6 %) dependence. University students who use AI chatbots exhibited significantly higher levels of depression (p < 0.01) and a greater proportion scoring in the moderate to high levels of depression compared to non-users (p < 0.01). Among these users, depression was directly associated with higher AI chatbot usage and dependence (β = 0.14 to 0.20, p < 0.05). However, no direct association was found between AI chatbot-related behaviors and mental well-being or resilience (p > 0.05). Nevertheless, resilience may be indirectly linked to AI chatbot usage/dependence via depression (β = -0.077 to -0.052; p < 0.05). In conclusion, AI chatbot usage is relatively common among university students, though overuse and severe dependence are infrequent. AI chatbot usage and dependence are associated with higher levels of depression; however, the causal relationship warrants further investigation.

Interactive effect of sleep duration, lifestyle factors and comorbidity on depressive symptoms: Insights from the China health and retirement longitudinal study

BACKGROUND

As population aging intensifies, depression emerges as a major global public health issue, especially affecting middle-aged and elderly individuals. While studies have investigated factors like sleep duration, physical activity, smoking, drinking habits, and comorbidity, the complex interplay and cumulative effect of these factors on the risk of depressive symptoms remain not fully understood.

METHODS

This research utilizes data from the China Health and Retirement Longitudinal Study (CHARLS), encompassing observations from 2015 to 2020. The subjects included 8234 middle-aged and elderly individuals, accounting for a total of 22,570 observations. Lifestyle factors were represented by physical activity, smoking, and drinking habits, with the volume of moderate-to-vigorous physical activity (MVPA) quantified by quoting metabolic equivalents (MET). Multivariate logistic regression models were conducted for baseline analysis, and mixed-effects logistic regression models with random participant intercepts were constructed for the longitudinal analysis of the cohort. Moreover, interaction terms between these factors were included to assess their combined impact on the risk of depressive symptoms.

RESULTS

Longitudinal analysis revealed a notable correlation between short sleep duration (<7 h) and an elevated risk of depressive symptoms, evidenced by an adjusted odds ratio (OR) of 3.13 (95 % CI: 2.73-3.74). Conversely, long sleep duration (>9 h) was not associated with a marked change in risk of depressive symptoms (OR = 1.11, 95 % CI: 0.78-1.59, p = 0.59). High levels of physical activity (192-336 MET-h/week) were significantly linked to an elevated risk of depressive symptoms (OR = 1.70, 95 % CI: 1.19-2.42). Discontinuing smoking was significantly correlated with a lower risk of depressive symptoms (OR = 0.68, 95 % CI: 0.52-0.90). Subjects with two or more concurrent conditions exhibited a substantially higher risk of depressive symptoms (OR = 3.19, 95 % CI: 3.13-3.25). Investigating the combined influence of sleep duration, lifestyle elements, and concurrent conditions revealed that enhanced physical activity levels significantly decreased risk of depressive symptoms in participants with short sleep duration, adjusting the OR from 3.16 to 0.83 (95 % CI, 0.53-1.30). Among participants with short sleep duration, smoking and alcohol consumption patterns were linked to a decreased risk of depressive symptoms, although these associations lacked statistical significance. Relative to subjects without concurrent conditions, those harboring two or more such conditions faced a significantly heightened risk of depressive symptoms in the context of short sleep duration (OR = 3.00, 95 % CI: 2.24-4.03), a risk not observed in subjects with extended sleep duration. Moderate napping (0.5-1 h) among participants with short sleep duration was found to significantly mitigate risk of depressive symptoms (OR = 0.64, 95 % CI: 0.44-0.95), whereas in subjects with prolonged sleep duration, extended napping did not significantly alter risk of depressive symptoms.

LIMITATIONS

The results, derived from a middle-aged and elderly Chinese population, may not be generalizable to other demographic groups or cultural contexts.

CONCLUSION

This study shows that short sleep duration, unhealthy lifestyle factors, and comorbidities significantly increase the risk of depressive symptoms in middle-aged and elderly individuals. Moderate physical activity, smoking cessation, moderate drinking, and appropriate napping can mitigate this risk, especially for those with short sleep duration. These findings highlight the need to address sleep quality, promote healthy habits, and manage comorbidities in mental health interventions for this population.

Sleep Profiles Among Ethnically-Racially Minoritized Adolescents: Associations with Sociocultural Experiences and Developmental Outcomes

OBJECTIVE

This study used latent profile analyses to (1) identify heterogeneous patterns of sleep profiles; (2) examine how discrimination was related to sleep profiles; and (3) investigate how developmental outcomes varied across sleep profiles among ethnically-racially minoritized adolescents.

METHOD

Participants were 350 ethnically-racially minoritized adolescents (69% female; 22% Black-African American, 41% Asian American, and 37% Latinx; Mage = 14.27 years old, SD = 0.61) completed self-reported presurvey measures of everyday discrimination, ethnic-racial discrimination, and self-reported post-survey measures of depressive symptoms, somatic symptoms, self-esteem, and rumination. Objectively and subjectively measured sleep were assessed utilizing a short-term longitudinal (i.e., two-week) design, where adolescents wore a wrist actigraph and completed daily diaries for 14 consecutive days.

RESULTS

Drawing on multiple objectively and subjectively measured sleep indicators, three profiles were identified: Nighttime Sleeper (76.57%), Disrupted Sleeper (14.29%), and Daytime Sleeper (9.14%). Adolescents experiencing higher levels of ethnic-racial discrimination were more likely to be characterized in the Disrupted Sleeper, relative to the Nighttime Sleeper profile. Compared with Asian and Latinx Americans, Black adolescents were more likely to be in the Daytime Sleeper, relative to the Nighttime Sleeper profile. Those in the Disrupted Sleeper profile exhibited the worst developmental outcomes.

CONCLUSIONS

The findings inform clinical interventions focusing on sleep experiences, especially as they relate to protective processes for coping with discrimination. Clinical efforts (e.g., sleep education or therapy to develop routines for adaptive napping) may be beneficial to facilitating healthy sleep behaviors and mitigating sleep disturbances, which in turn, improve developmental well-being among ethnically-racially minoritized adolescents.

The longitudinal relationship between night-time sleep duration, midday napping, and frailty among middle-aged and older people in China: a prospective analysis

Background

Frailty is an important issue presented by ageing. Night-time sleep and midday napping are important modifiable factors influencing health, but their impacts on frailty remain unclear.

Methods

We used five waves of data from the China Health and Retirement Longitudinal Study (2011-20), with 15 333 participants in the baseline sample. We used fixed effects regression models to explore longitudinal relationships between night-time sleep duration, midday napping, and frailty index (FI). We added interaction terms of sleeping and napping to the regression model to explore their combined effects. We further used the Cox proportional regression model to quantify risks for frailty.

Results

Compared to sleeping seven to nine hours, sleeping <6 hours (FI = 0.016), six to seven hours (FI = 0.004), and >9 hours (FI = 0.005) were significantly associated with a mean increase in FI separately. Napping >90 minutes significantly increased FI by 0.003 compared to non-nappers. Effects of sleeping six to seven hours and >9 hours on frailty were separately enhanced by napping >90 minutes and any napping duration (except 60-90 minutes). Sleeping <6 hours and six to seven hours increased frailty risk by 44% (hazard ratio (HR) = 1.44) and 12% (HR = 1.12), respectively. Frailty risk was increased by napping >90 minutes by 14% (HR = 1.14) compared to non-nappers.

Conclusions

Short (<7 hours) or long (>9 hours) sleep and prolonged midday napping (>90 minutes) were associated with frailty among the Chinese middle-aged and older population. The compensation effect of napping for short night-time sleep was not found in this study, and certain napping durations even increased risks of sleeping six to seven hours and >9 hours for frailty.

Daytime napping and depressive symptoms in bipolar disorder: A cross-sectional analysis of the APPLE cohort

BACKGROUND

The relationship between daytime napping and depression remains debatable. Thus, we investigated whether daytime napping is associated with depressive symptoms in patients with bipolar disorder.

METHODS

In a cross-sectional study, we enrolled 204 outpatients with bipolar disorder who were participants in the Association between Pathology of Bipolar Disorder and Light Exposure in Daily Life (APPLE) cohort study. Each participant's daytime napping was measured using an actigraph over 7 consecutive days. Depressive symptoms were evaluated using the Montgomery-Åsberg Depression Rating Scale, and scores of ≥8 points were considered indicative of a depressed state.

RESULTS

One-hundred and ten (53.9 %) participants were depressed. In multivariable logistic regression analysis, as the number of nap days, number of naps per day, and nap duration increased, the odds ratio (OR) for depressed state significantly increased. Additionally, compared to the participants who did not nap, the participants who napped on five or more days a week or who had an average nap duration over 60 min had more than three times higher ORs in the depressed state (number of nap days: OR, 3.66; 95 % confidence interval [CI], 1.32-10.17; nap duration: OR, 3.14; 95 % CI, 1.12-8.81).

CONCLUSIONS

We found a significant and independent association between daytime napping and depressive symptoms in patients with bipolar disorder. Further studies are warranted to identify the effect of short napping on depressive symptoms in patients with bipolar disorder.

Shorter night-time sleep duration and later sleep timing from infancy to adolescence

BACKGROUND

Here, we (a) examined the trajectories of night-time sleep duration, bedtime and midpoint of night-time sleep (MPS) from infancy to adolescence, and (b) explored perinatal risk factors for persistent poor sleep health.

METHODS

This study used data from 12,962 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Parent or self-reported night-time sleep duration, bedtime and wake-up time were collected from questionnaires at 6, 18 and 30 months, and at 3.5, 4-5, 5-6, 6-7, 9, 11 and 15-16 years. Child's sex, birth weight, gestational age, health and temperament, together with mother's family adversity index (FAI), age at birth, prenatal socioeconomic status and postnatal anxiety and depression, were included as risk factors for persistent poor sleep health. Latent class growth analyses were applied first to detect trajectories of night-time sleep duration, bedtime and MPS, and we then applied logistic regressions for the longitudinal associations between risk factors and persistent poor sleep health domains.

RESULTS

We obtained four trajectories for each of the three sleep domains. In particular, we identified a trajectory characterized by persistent shorter sleep, a trajectory of persistent later bedtime and a trajectory of persistent later MPS. Two risk factors were associated with the three poor sleep health domains: higher FAI with increased risk of persistent shorter sleep (OR = 1.20, 95% CI = 1.11-1.30, p < .001), persistent later bedtime (OR = 1.28, 95% CI = 1.19-1.39, p < .001) and persistent later MPS (OR = 1.30, 95% CI = 1.22-1.38, p < .001); and higher maternal socioeconomic status with reduced risk of persistent shorter sleep (OR = 0.99, 95% CI = 0.98-1.00, p = .048), persistent later bedtime (OR = 0.98, 95% CI = 0.97-0.99, p < .001) and persistent later MPS (OR = 0.99, 95% CI = 0.98-0.99, p < .001).

CONCLUSIONS

We detected trajectories of persistent poor sleep health (i.e. shorter sleep duration, later bedtime and later MPS) from infancy to adolescence, and specific perinatal risk factors linked to persistent poor sleep health domains.

Associations between daytime napping, sleep duration, and depression and 15 cardiovascular diseases: a Mendelian randomization study

Background

Numerous studies have documented the effects of daytime napping, sleep duration, and depression on cardiovascular diseases (CVDs). However, the evidence has been gleaned from observational studies that might be riddled with confounding variables and the possibility of reverse causation bias. Therefore, the present study employed a Mendelian randomization (MR) methodology to meticulously explore the relationships between daytime napping, sleep duration, and depression, and the risk profiles of CVDs.

Methods

Genome-wide significant genetic variants associated with daytime napping, sleep duration, and depression were used as the instrumental variables (IVs). Data on the genetic correlations between these IVs and 15 CVDs were derived from the United Kingdom (UK) Biobank, Finnish Genome Studies, and other large-scale collaborations. We conducted both univariate and multivariate MR analyses to assess the overall effects and mediated relationships after adjusting for potential confounders, including body mass index (BMI), smoking status, and type 2 diabetes. The effect sizes were estimated using inverse variance-weighted (IVW) regression.

Results

The MR analysis revealed that an increased risk of heart failure (HF) [odds ratio (OR): 1.366; 95% confidence interval (CI): 1.013-1.842; P=0.04], coronary atherosclerosis (OR: 1.918; 95% CI: 1.257-2.927; P=0.003), myocardial infarction (MI) (OR: 1.505; 95% CI: 1.025-2.211; P=0.04), and coronary artery disease (CAD) (OR: 1.519; 95% CI: 1.130-2.043; P=0.006) was significantly associated with genetically predicted daytime napping. Prolonged sleep duration was found to be related to a reduced risk of HF (OR: 0.995; 95% CI: 0.993-0.998; P=2.69E-04), peripheral vascular disease (PVD) (OR: 0.984; 95% CI: 0.971-0.997; P=0.02), and CAD (OR: 0.997; 95% CI: 0.994-0.999; P=0.006). Additionally, a statistically significant positive relationship was observed between depressive disorders and the occurrence of atrial fibrillation (AF) (OR: 1.298, 95% CI: 1.065-1.583, P=0.01), indicating a heightened susceptibility. The multivariable MR analyses substantiated the reliability of the observed associations between daytime napping and the incidence of HF and CAD, following adjustments for genetically predicted BMI and smoking. The sensitivity analysis did not reveal any evidence of horizontal pleiotropy or heterogeneity, thus supporting the validity of the study's results.

Conclusions

This MR investigation posits a potential causal nexus between daytime napping, sleep duration, and depression, and the genesis of CVDs, offering new perspectives on the prevention and management of CVDs.

The relationships between wanting to nap, actually napping, and depressed and anxious mood

Study Objectives

These studies disentangle the relationships between wanting to nap (nap desire), actually napping (nap behavior), and depressed and anxious mood. Study 1 partially replicated and extended findings connecting napping and depressed and anxious mood. Study 2 explored the distinction between nap desire and behavior using a new, larger sample and a different technique.

Methods

Study 1 used a longitudinal, multimethod approach to understand napping and mood among undergraduate students in the United States (N = 104). In Study 2, a cross-sectional survey was conducted on adults over 25 in the continental United States (N = 1406), including items from the DASS-21 and questions about nap desire and behavior.

Results

Study 1 found a significant relationship between same-day napping behavior and depressed mood (M nap = 1.61, SE nap = 0.08 vs. M no nap = 1.44, SE no nap = 0.06, p = .018) but not anxious mood (p = .766). Study 2 partially replicated those findings; Analysis of Covariance (ANCOVA) showed that napping desire had a significant effect on anxious (F(1, 1291) = 6.86, p = .009, partial η2 = .005) and depressed mood (F(1, 1291) = 13.46, p < .001, partial η2 = .010), accounting for age, gender, and restedness, but napping behavior did not add to that effect.

Conclusions

Wanting to nap is related to greater depressed and anxious mood, but actual napping did not add to that relationship. These results have implications for clinicians using sleep assessment as a screening tool for mental health and highlight the need for further research on napping motivation.

Prevalence and associated factors of napping among older adults in the Philippines

BACKGROUND

The aim of the study is to estimate the prevalence and associated factors of insomnia among older adults in the Philippines.

METHODS

In all, 5206 cross-sectional nationally representative data from older adults (≥ 60 years) of the 2018 Longitudinal Study on Ageing and Health in the Philippines (LSAHP) was analysed. Napping frequency and duration were assessed by self-report.

RESULTS

The prevalence of regular nappers was 35.7%, low or moderate napping (1-59 min) was 10.5% and long napping (≥ 60 min) duration was 25.2%. In the final adjusted model, older age was not significantly associated with low or moderate napping duration but older age was positively associated with long napping duration. High wealth status, physical activity and late insomnia were positively associated with low or moderate napping duration. High wealth status, urban residence, daily activity limitations, and physical activity were positively associated, and currently working status, poor self-rated health status and current alcohol use were negatively associated with long napping duration.

CONCLUSION

One in four older adults reported long napping duration. Sociodemographic, health status and behaviour and sleep parameters were associated with low or moderate and/or long napping duration.

Results of two cross-sectional database analyses regarding nap-induced modulations of tinnitus

The influence of naps on tinnitus was systematically assessed by exploring the frequency, clinical and demographic characteristics of this phenomenon. 9,724 data from two different tinnitus databases (Tinnitus Hub: n = 6115; Tinnitus Research Initiative (TRI): n = 3627) were included. After separate analysis of the databases, these results were then compared with each other. In the Tinnitus Hub survey database, a total of 31.1% reported an influence on tinnitus by taking a nap (26.9% in the TRI database), with much more frequent worsening after a nap than improvement (23.0% a little or a lot worse; TRI: 17.7% worse; 8.1% a little or a lot better; TRI: 9.2% better). The influence of napping on tinnitus was associated in both databases with other clinical features, such as the dependence of tinnitus on night quality, stress and somatosensory maneuvers. The present study confirms the clinical observation that more tinnitus sufferers report worsening after a nap than tinnitus sufferers reporting an improvement. It was consistently shown that tinnitus sufferers reporting nap-induced modulation of tinnitus also report more frequently an influence of night sleep on their tinnitus. Further clinical and polysomnographic research is warranted to better understand the interaction between sleep and tinnitus.

Depression and hepatobiliary diseases: a bidirectional Mendelian randomization study

Background

More and more evidence suggests a close association between depression and hepatobiliary diseases, but its causal relationship is not yet clear.

Method

Using genome-wide association studies (GWAS) to summarize data, independent genetic variations associated with depression were selected as instrumental variables. Firstly, we designed a univariate Mendelian randomization (UVMR) analysis with two samples and simultaneously conducted reverse validation to evaluate the potential bidirectional causal relationship between depression and various hepatobiliary diseases. Secondly, we conducted a multivariate Mendelian randomization (MVMR) analysis on diseases closely related to depression, exploring the mediating effects of waist to hip ratio, hypertension, and daytime nap. The mediating effects were obtained through MVMR. For UVMR and MVMR, inverse variance weighted method (IVW) is considered the most important analytical method. Sensitivity analysis was conducted using Cochran'Q, MR Egger, and Leave-one-out methods.

Results

UVMR analysis showed that depression may increase the risk of non-alcoholic fatty liver disease (OR, 1.22; 95% CI, 1.03-1.46; p=0.0248) in liver diseases, while depression does not increase the risk of other liver diseases; In biliary and pancreatic related diseases, depression may increase the risk of cholelithiasis (OR, 1.26; 95% CI, 1.05-1.50; p=0.0120), chronic pancreatitis (OR, 1.61; 95% CI, 1.10-2.35; p=0.0140), and cholecystitis (OR, 1.23; 95% CI, 1.03-1.48; p=0.0250). In addition, through reverse validation, we found that non-alcoholic fatty liver disease, cholelithiasis, chronic pancreatitis, cholecystitis, or the inability to increase the risk of depression (p>0.05). The waist to hip ratio, hypertension, and daytime nap play a certain role in the process of depression leading to non-alcoholic fatty liver disease, with a mediating effect of 35.8%.

Conclusion

Depression is a susceptibility factor for non-alcoholic fatty liver disease, and the causal effect of genetic susceptibility to depression on non-alcoholic fatty liver disease is mediated by waist-hip ratio, hypertension, and daytime nap.

Excessive daytime napping independently associated with decreased insulin sensitivity in cross-sectional study - Hyogo Sleep Cardio-Autonomic Atherosclerosis cohort study

Background

Although excessive daytime napping has been shown to be involved in diabetes occurrence, its impact on insulin secretion and sensitivity has not been elucidated. It is speculated that excessive napping disrupts the sleep-wake rhythm and increases sympathetic nerve activity during the day, resulting in decreased insulin sensitivity, which may be a mechanism leading to development of diabetes. We previously conducted a cross-sectional study that showed an association of autonomic dysfunction with decreased insulin sensitivity, though involvement of autonomic function in the association between napping and insulin sensitivity remained unclear. Furthermore, the effects of napping used to supplement to short nighttime sleep on insulin secretion and sensitivity are also unknown. In the present cross-sectional study, we examined the relationships of daytime nap duration and autonomic function with insulin secretion and sensitivity in 436 subjects enrolled in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Cohort Study who underwent a 75-g oral glucose tolerance test (75-g OGTT), after excluding those already diagnosed with diabetes.

Methods

Daytime nap duration was objectively measured using actigraphy, with the subjects divided into the short (≤1 hour) and long (>1 hour) nap groups. Insulin secretion and sensitivity were determined using 75-g OGTT findings. Standard deviation of normal to normal R-R interval (SDNN), a measure of autonomic function, was also determined based on heart rate variability. Subgroup analysis was performed for the associations of napping with insulin secretion and sensitivity, with the results stratified by nighttime sleep duration of less or greater than six hours.

Results

Subjects in the long nap group exhibited lower insulin sensitivity parameters (QUICKI: β=-0.135, p<0.01; Matsuda index: β=-0.119, p<0.05) independent of other clinical factors. In contrast, no associations with insulin secretion were found in either group. Furthermore, the association of long nap duration with insulin sensitivity was not confounded by SDNN. Specific subgroup analyses revealed more prominent associations of long nap habit with lower insulin sensitivity in subjects with a short nighttime sleep time (β=-0.137, p<0.05).

Conclusion

Long daytime nap duration may be a potential risk factor for decreased insulin sensitivity.

Associations of sleep duration, daytime napping, and snoring with depression in rural China: a cross-sectional study

BACKGROUND

Most adult patients with depression complain about sleep symptoms, including insufficient and excessive sleep. However, previous studies investigating the impact of sleep duration on depression have yielded conflicting results. Therefore, this study aimed to analyse the link between depression and sleep duration, daytime napping, and snoring among rural Chinese adults.

METHODS

A cross-sectional study was conducted with 9104 individuals. Interviews were conducted with the participants regarding their sleep patterns and their daytime napping routines. The individuals were then assessed for depression using the Patient Health Questionnaire-9. The risk of depression was assessed using a multifactor binary logistic regression analysis. A generalized additive model was used to evaluate the nonlinear relationship between depression and sleep duration/nap time. Additionally, subgroup analysis was conducted to investigate the correlation between sleep duration, daytime napping, snoring, and depression.

RESULTS

Less than 6 h or more than 8 h of nighttime sleep, daytime napping for more than 1 h, and snoring were all significantly associated with an increased risk of depression. A U-shaped relationship was found between the duration of nighttime sleep and depression. In addition, we found that the nighttime duration of sleep, daytime naps, and snoring had a significant combined effect on the risk of depression. The subgroup analysis further revealed that lack of sleep at night significantly increased the risk of depression in all subgroups. However, snoring and excessive nighttime sleep and napping were only associated with the risk of depression in some subgroups.

CONCLUSIONS

Lack of nighttime sleep (short sleep duration), excessive sleep, and napping for more than one hour during the day were associated with a high risk of depression and had a combined effect with snoring.