Abstract
In the first comprehensive examination of its kind, we investigated the association between maternal depression and preschoolers’ sleep problems, as well as factors that influence children’s sleep. A cross-sectional questionnaire survey was administered to mothers of children in nine kindergartens and nursery schools across six Japanese prefectures. The sample included 232 mother–child pairs (children’s average age = 61.72 months; 51.29% boys; mothers’ average age = 38.38 years). Mothers’ depression and parenting behaviors were assessed using the Patient Health Questionnaire-9 and Parenting Behavior Checklist to Promote Preschoolers’ Sleep, respectively. Children’s sleep problems and emotional and behavioral problems were assessed using the Japanese Sleep Questionnaire for Preschoolers and the Strengths and Difficulties Questionnaire, respectively. Mothers reported on their children’s duration of daytime activity and screen time. Thirty-two percent of mothers had more than minimal depressive symptoms. Path analysis revealed that children’s emotional and behavioral problems, and sleep problems were associated with maternal depression (β = 0.24, β = 0.21). Furthermore, children’s emotional and behavioral problems, duration of daytime activity, and parenting behaviors to promote children’s sleep were associated with children’s sleep problems (β = 0.45, β = − 0.09, β = − 0.45). The values of GFI (0.99), AGFI (0.95), and RMSEA (0.05) showed a good fitness of the model. The results suggest the necessity of assessing children’ sleep problems and emotional and behavioral problems when considering mothers’ mental health problems in the future.
Keywords: Preschoolers, Sleep problems, Maternal depression, Parenting, Strengths and difficulties questionnaire
Introduction
Maternal depression is a serious mental health problem for women and their families. Specifically, studies show that mothers with depression are at a high risk of encountering difficulties with childrearing [1], and are more negative toward their children than non-depressed mothers [2]. Furthermore, maternal depression has been reported as a risk factor for child neglect [3]. Therefore, there is a significant social need to clarify the factors associated with maternal depression and the interrelationship between mothers and their children. This encompasses crucial topics in both mental health care and child abuse prevention.
Studies have suggested that sleep problems such as frequent nocturnal awakenings and difficulties in settling at night in preschoolers are associated with maternal depression [4]. Lam et al. examined the relationship between children’s sleep problems and parental well-being, stating that early intervention is important because persistent or recurrent sleep problems in preschool childhood are common and negatively affect the mental health of the mother [5]. Although adequate sleep is essential for children’s normal growth and development [6], the estimated prevalence of sleep problems in preschoolers ranges between 20 and 45% [7–9]. Furthermore, 35% of preschoolers with a sleep disorder continue to demonstrate sleep problems throughout their school years [9]. Therefore, sleep problems in young children should be addressed at an early stage.
Studies have reported various factors associated with sleep problems in children, including medical and behavioral problems that interfere with sleep [10] and parent–child interaction quality [11]. There are also concerns regarding the impact of lifestyle changes on children’s sleep in our increasingly digitized world [12]. Evidence from a systematic review indicates that longer daily and evening screen times are unfavorably associated with sleep outcomes in children younger than five, and conversely, increased outdoor play involving moderate and vigorous physical activity positively affects sleep in toddlers and preschoolers [13]. The latter findings indicate that sleep duration and daytime activity are interrelated. Furthermore, parenting behaviors were found to associate with children’s sleep. Hoyniak et al. showed that parenting behaviors related to bedtime routine, sleep environment, and emotional security influenced children’s sleep [14]. Smedje et al. found that 15% of children with behavioral problems also reported having sleep problems [15] and Fulfs et al. demonstrated the association between sleep problems and emotional/behavioral difficulties in a large sample of healthy participants [16].
These studies collectively clarify that numerous factors are associated with sleep problems in young children, including those attributable to the children themselves and their environments. However, to the best of our knowledge, no study has comprehensively examined the relationships among sleep-related factors, children’s sleep, and maternal depression. Therefore, this study generated a hypothetical model to examine these relationships. Sleep-related factors attributable to the children themselves, environmental factors, and child-rearing behaviors were extracted from various factors reported to be associated with sleep problems in preschoolers. The model contained the following four factors associated with preschoolers’ sleep problems: children’s emotional and behavioral problems (EBPs), duration of daytime activity, screen time, and parenting behaviors to promote children’s sleep. Goodman et al. [17] conducted a meta-analysis of the results of 193 published articles on the association between maternal depression and child mental health. The sample consisted of 80,851 mother–child pairs, ranging in age from nine days to 20 years of age of the child. The results confirmed a weak but significant association between mothers' depressive tendencies (symptom scores) and children's internalizing problems with r = 0.23 (p < 0.001) and children's externalizing problems with r = 0.15 (p < 0.001). Therefore, we hypothesized a direct association between children’s EBPs and maternal depression.
Materials and methods
Participants
A questionnaire survey was conducted in Japan from February to December 2021. Nine kindergartens and nursery schools across six of the 47 prefectures in Japan agreed to be surveyed. Before the study commenced, the staff of the kindergartens and nursery schools were given an overview of the study, its purpose, and procedures. Consequently, a written explanation of the study and a self-administered questionnaire were distributed to the 891 parents of the attending children, and consent was received from 428 (overall response rate: 48.0%). Parents with two or more children attending the same facility were asked to provide responses regarding their eldest child. The questionnaires were returned by mail.
We excluded 196 respondents based on the following exclusion criteria: (1) the child was younger than four years old (n = 87), (2) entries made by individuals other than the mother or entries with missing values (n = 33), and (3) surveys with one or more items missing from the measures used in path analysis (n = 76). The final analysis included data from 232 mother–child pairs (see Fig. 1). The study protocol was approved by the ethics committee of Takiyo University, Japan (approval no. 577).
Fig. 1.
Participant flow diagram
Measurements
Maternal depression
The Patient Health Questionnaire-9 (PHQ-9) was used to assess maternal depression [18]. The Japanese version was created by Muramatsu et al. [19]. This nine-item self-report measure assesses depressive symptoms experienced over the previous two weeks, with a four-point response scale from 0 (not at all) to 3 (nearly every day), and total scores ranging from 0–27. Mothers reported how often they were bothered by problems such as little interest or pleasure in doing things. Scores of 5–9 indicate minimal, 10–14 indicate mild, 15–19 indicate moderate to severe, and above 20 indicate severe depressive symptoms.
Sleep problems
Mothers reported their children’s sleep problems using items from a sleep questionnaire based on the Japanese Sleep Questionnaire for Preschoolers (JSQ-P), a parent-reported questionnaire to assess sleep disturbances, problems, and habits in preschool children [20]. It consists of 10 factors, but the following four factors were excluded to reduce the burden on respondents and to match the objectives of this study: Factor I, the sensory symptoms of restless legs syndrome; Factor II, the motor symptoms of restless legs syndrome; Factor III, symptoms of obstructive sleep apnea; Factor IX, related to problematic sleep habits. Therefore, the following six factors were used: Factor IV, parasomnia (e.g., waking up more than twice during nighttime sleep); Factor V, reflecting insomnia or circadian rhythm sleep–wake disorders (e.g., struggle to get child to sleep); Factor VI, referring to undesirable morning symptoms and behaviors (e.g., unable to get out of bed in the morning); Factor VII, excessive daytime sleepiness (e.g., sleepy during the daytime); Factor VIII, representing undesirable daytime behaviors related to sleep problems (e.g. restlessness during the daytime); Factor X, reflecting insufficient sleep (e.g. sleeping at least one hour longer on weekends than on weekdays.).
Items were rated on a six-point Likert scale ranging from 1 to 6 (1, strongly disagree; 2, disagree; 3, somewhat disagree; 4, somewhat agree; 5, agree; 6, strongly agree). The total score of the JSQ-P ranges from 25 to 150, with higher scores indicating sleep disorders or poor sleep habits.
Children’s emotional and behavioral problems
Children’s EBPs were assessed using the Japanese version of the Strengths and Difficulties Questionnaire (SDQ) which has demonstrated high validity and reliability [21]. The SDQ includes five subscales rated on a 3-point scale (0: not applicable, 1: slightly applicable, 2: applicable); four subscales to assess behavioral problems (emotional symptoms, conduct problems, hyperactivity/inattention, and peer relationship problems), and one subscale to assess prosocial behavior. The total difficulty score (0–40 points) is calculated using the sum of the scores for the four subscales.
Parenting behavior to promote preschoolers’ sleep
The Parenting Behavior Checklist to Promote Preschoolers’ Sleep (PCPP) was used to assess mothers’ parenting behavior that promotes sleep in children [22]. The PCPP was developed based on the recommendations of the ABCs of SLEEPING for children’s sleep—which are strongly supported by research [23]—and has been confirmed for reliability and validity [22]. The PCPP comprises the following six statements: “I see to it that my child obtains age-appropriate amounts of sleep;” “I put my child to bed no later than 9 pm;” “I ensure that my child’s nap, bed, and wake times are consistent;” “I establish my child’s bedtime routines (e.g., taking a bath, brushing their teeth, and then reading picture books);” “I try to enable my child to fall asleep in their own bed without dependence on parental presence;” and “I care about my child’s safety and happiness.” The items are rated on a six-point Likert scale (1, strongly disagree; 2, disagree; 3, somewhat disagree; 4, somewhat agree; 5, agree; 6, strongly agree), total scores range from 6 to 36, and higher scores indicate that parents perform the recommended behaviors to help their children sleep.
Children’s daytime activity and screen time
Mothers reported their children’s daytime activity duration and the amount of exposure to screen time. Screen time refers to the time spent by children on smartphones, tablets, and watching television. In this study, significant differences were found between weekdays and weekends in both children's screen time and daytime activity time. Therefore, (weekday screen time*5 days + weekend screen time*2)/7 was used to obtain average for the analysis. The same method was used to determine daytime activity time.
Data analysis
A hypothetical model was constructed using path analysis based on the results of previous studies. The hypothesized model assumed that parenting behaviors that promote sleep in children, children’s EBPs, duration of daytime activity, and screen time affect children’s sleep problems and that children’s sleep problems and EBPs affect maternal depression. We then estimated the path coefficients among the variables in the hypothetical model and examined these associations. The goodness-of-fit index (GFI), adjusted goodness-of-fit index (AGFI), and root mean square error of approximation (RMSEA) were used to evaluate the model’s goodness-of-fit. For RMSEA, a value less than 0.05 is considered a good fit, and below 0.08 an adequate fit [24]. Both GFI and AGFI had values between 0 and 1; the closer the value is to 1, the more powerful the model. Path analysis was conducted using AMOS version 28.0, and the significance level was set at 5%.
Results
Participants’ characteristics
Table 1 presents the participants’ demographic data. The sample comprised 119 male and 113 female children with a mean age of 61.72 months. Furthermore, 31.90% and 66.38% attended nursery schools and kindergartens, respectively. Of the 232 children, 215 (92.7%) shared bedrooms with adults and 16 (6.9%) shared bedrooms with only siblings. Other details are presented in Table 1.
Table 1.
Participants’ characteristics (n = 232)
| Variable | ||
|---|---|---|
| Maternal age in years, mean (SD) | 38.38 (4.77) | |
| Maternal occupation, n (%) | ||
| Homemaker | 102 (43.97) | |
| Part-time employee | 56 (24.14) | |
| Permanent employee | 45 (19.40) | |
| Part-time job | 4 (1.72) | |
| Childcare leave | 10 (4.31) | |
| Other | 15 (6.47) | |
| Child’s age in months, mean (SD) | 61.72 (8.76) | |
| Child’s sex | ||
| Male, n (%) | 119 (51.29) | |
| Child’s school, n (%) | ||
| Kindergarten | 154 (66.38) | |
| Nursery school | 74 (31.90) | |
| Other | 2 (0.86) | |
| Bedroom-sharing, n (%) | ||
| With adult | 215 (92.67) | |
| With sibling only | 16 (6.90) | |
| Missing values | 1 (0.43) | |
[Table 1 near here].
Maternal depression, children’s sleep problems and sleep variables, and sleep-related factors
The mean PHQ-9 score was 3.78 (standard deviation, SD = 3.94). The distribution of mothers’ PHQ-9 scores showed that 23.7% (n = 55) had mild, 6.9% (n = 16) had moderate, 0.4% (n = 1) had moderate to severe, and 0.8% (n = 2) had severe depressive symptoms.
Table 2 shows the results for children’s sleep problems, sleep variables, and sleep-related factors. For each of the six subscales of the JSQ-P used in this study, the numbers of children who scored above the cutoff values were as follows: Factor IV, parasomnia (25%, n = 58), Factor V, reflecting insomnia or circadian rhythm sleep–wake disorders (15.5%, n = 36), Factor VI, referring to undesirable morning symptoms and behaviors (28%, n = 65), Factor VII, excessive daytime sleepiness (18.5%, n = 43), Factor VIII, representing undesirable daytime behaviors related to sleep problems (22%, n = 51), and Factor X, reflecting insufficient sleep (18.5%, n = 43). Table 2 also provides the average total SDQ score and an average score for each subscale of the SDQ.
Table 2.
Children’s sleep and behavior problems and sleep variables (N = 232)
| Variable | Mean (SD) | |
|---|---|---|
| JSQ-Pa | ||
| Parasomnias (range 5–30) | 7.25 (3.01) | |
| Insomnia or circadian rhythm sleep–wake disorders (range 10–60) | 15.25 (5.05) | |
| Undesirable morning symptoms and behaviors (range 3–18) | 6.51 (3.43) | |
| Excessive daytime sleepiness (range 3–18) | 4.73 (2.21) | |
| Undesirable daytime behaviors related to sleep problems (range 2–12) | 3.63 (1.96) | |
| Insufficient sleep (range 2–12) | 5.09 (2.64) | |
| SDQb | ||
| Total Difficulties score (range 0–40) | 8.26 (5.19) | |
| Emotional symptoms (range 0–10) | 1.51 (1.82) | |
| Conduct problems (range 0–10) | 2.44 (1.87) | |
| Hyperactivity/inattention (range 0–10) | 2.93 (2.22) | |
| Peer relationship problems (range 0–10) | 1.38 (1.45) | |
| Prosocial behavior (range 0–10) | 6.79 (1.45) | |
| Screen time (min)c | 98.69 (63.45) | |
| Activity time (min)d | 155.33 (87.25) | |
| Child’s sleep habits | Weekday | Weekend |
| Bed time | 20:55 (0:48) | 21:09 (0:50) |
| Final wake time | 7:02 (0:34) | 7:24 (0:56) |
| Midpoint time | 2:08 (0:36) | 2:27 (0:46) |
| Time in bed (hr) | 10.16 (0.53) | 10:23 (0:56) |
| Total sleep time (hr) | 9.46 (0.44) | 9.54 (0.53) |
| Sleep onset latency (min) | 20.65 (15.01) | 20.35(16.44) |
| Daytime naps (min) | 19.63 (40.37) | 12.20 (32.04) |
aJSQ-P: Japanese Sleep Questionnaire for Preschoolers
bSDQ: Strengths and Difficulties Questionnaire
cScreen time (min): Calculated by the following formula (weekday screen time*5 + weekend screen time*2) /7
dActivity time (min): Calculated by the following formula (weekday activity time*5 + weekend activity time*2) /7
The mean total sleep time on weekdays and weekends was 9.46 ± 0.44 and 9.54 ± 0.53 h, respectively. Additionally, mean bedtime and final wake time on weekdays were 20:55 ± 0:48 and 7:02 ± 0:34, and on weekends were 21:09 ± 0:50 and 7:24 ± 0:56, respectively. Moreover, the average screen time duration was 98.7 min and the average duration of activity time was 155.3 min.
[Table 2 near here].
Results of the path analysis
The model’s results are presented in Fig. 2, where GFI = 0.99, AGFI = 0.95, and RMSEA = 0.05. The results of the path analysis revealed a significant positive path from children’s EBPs to their sleep problems (β = 0.45), and a significant negative path from both the duration of children’s daytime activity and parenting behavior to promote sleep to children’s sleep problems (β = − 0.09; β = − 0.45). No significant relationship was found between children’s screen time and sleep problems. A significant positive path existed from children’s EBPs and sleep problems to maternal depression (β = 0.24, β = 0.21). Furthermore, children’s EBPs were negatively correlated with parenting behavior to promote sleep (r = − 0.22, p < 0.01).
Fig. 2.
Path analysis model of the relationship between children’s sleep problems, sleep-related factors, and mothers’ depression
Discussion
This study revealed a significant association between maternal depression and preschool children’s sleep problems and EBPs, including factors related to children’s sleep. The results are considered to be aligned with previous reports that children's nighttime sleep problems affect maternal depression [25] and that children's emotional expression during the day is a factor causing maternal depression [26]. The results obtained in this study are consistent with those of previous studies, which indicates consistency in the integrative results. Specifically, they resemble the evidence in previous research showing the association with children’s sleep and parenting behaviors [15], activities [14], and studies on the interplay between children’s EBPs and sleep problems [16, 17]. Newton et al. [27] revealed that six of the seven inspected studies supported the effect of specific components of bedtime routines in mitigating children’s sleep problems, and calming bedtime activities is a protective factor against sleep problems [28]. St Laurent et al. further found that physical activity aids sleep in children younger than six years [29]. In a recent study, Zheng et al. [30] suggested that sleep duration is a predictor of EBPs in preschool children, although the inverse association is not significant, and the mechanisms linking sleep deprivation and EBPs remain unclear. Although the coexistence of sleep problems and EBPs in children is well established in the literature, details of their relationship remain lacking [31]. Based on these findings, when treating maternal depression, it may be beneficial to simultaneously address children’s sleep problems and EBPs. Additionally, environmental approaches that encourage positive parenting behaviors to improve children’s sleep and daytime activity may be effective.
Importantly, the current results point to Japanese preschool children getting inadequate sleep, as the mean sleep duration was 9.5 h (4–5 years: 9.5 h; 6–7 years: 9.2 h). The sleep duration recommended by the National Sleep Foundation is 10–13 h for children aged 3–5 years and 9–11 h for children aged 6–13 years [32]. Based on these guidelines, the sleep duration of many children in our sample from all age groups did not meet the recommended durations. Japanese children sleep less than children in other countries [33], therefore there is also a greater need to encourage parenting behaviors that promote children’s sleep. Notably, 92.7% of the children in this study shared a bedroom with their parents. Mileva-Seitz et al. indicated that bed-sharing rates are higher in Japan compared to Western countries [34]. The ABCs of SLEEPING recommend that children sleep independently in their own beds, and this is supported by strong evidence according to Allen et al. [25]. Inoue et al. also suggested the importance of fostering the ability of Japanese children to fall asleep independently, rather than merely focusing on them sleeping in their own beds [24].
The present study’s findings regarding the relationship between screen time and sleep problems differ from the results of numerous past studies. Newton et al. reviewed the risk and protective factors for behavioral sleep disorders in children aged 1–10 years, noting that 13 of the 16 reviewed studies showed that electronic device use is a risk factor for sleep problems in children, although the effect size ranged from very small to moderate [27]. In the latter studies, the survey items covered a wide range of topics, including television viewing before and after bedtime, the use of electronic devices, the time of day when the electronic devices were used, and the content viewed on television. Conversely, in the present study, we only inquired about daily screen time and did not request details regarding the time of day, content, or types of electronic devices. Considering our recently digitalized society, the relationship between children’s screen time and sleep should be examined in further detail for each of the above conditions.
This study has three main limitations. First, our findings were obtained through a cross-sectional survey and not through a prospective study. In this study, a significant path from child sleep problems to maternal depression was demonstrated and an association was found, but the direction of this association remains controversial. Schultz et al. demonstrated that maternal depression is a significant risk factor for children’s sleep problems, with evidence supporting a bidirectional association [35]. Therefore, future studies for cohort studies to examine not only the association at the time but also the long-term bidirectional effects, are required. Second, the present study examined only the relationships between some concepts of interest, whereas various other biological, psychological, and environmental factors can influence children’s sleep. Future studies should include more factors strongly related to the participating children’s ages. Third, this study measured children’s sleep problems through mothers’ responses; however, mothers with strong depressive symptoms may perceive their children’s problems to be relatively more severe, and their responses may have been subjectively biased. To address this problem, future studies could also conduct physiological assessments, such as polysomnography.
In conclusion, despite the methodological limitations of this study, the findings suggest the importance of assessing children's sleep problems and EBPs when considering maternal mental health care, including depression. Furthermore, recognizing that both mother and children may have support needs, and considering interventions for both, could potentially enhance the wellbeing of both.
Acknowledgements
The authors would like to thank the staff of the kindergartens and nursery schools and the parents that contributed to this study.
Funding
This study was funded by Pfizer Health Research Foundation (to SN), AMED under Grant Number JP21zf 0127005 (to SN), JSPS KAKENHI [Grant Number 21K20312 (to YM)], and JSPS KAKENHI [Grant Number 21K13722 (to HO)].
Declarations
Conflict of interest
SN received lecture fees from the Japanese Association of Behavioral and Cognitive Therapies and the Japan Baby Sleep Research Institute.
Human or animal participants
The study protocol was approved by the ethics committee of Teikyo University, Japan (approval no. 577).
Footnotes
Naoko Inada Mail: Teikyo University at the time of research.
Shun Nakajima Mail: National Center of Neurology and Psychiatry at the time of research.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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