Introduction: The COVID-19 pandemic has had a significant impact on individuals’ physical and mental well-being, particularly affecting their sleep patterns. However, prospective research on the...Show moreIntroduction: The COVID-19 pandemic has had a significant impact on individuals’ physical and mental well-being, particularly affecting their sleep patterns. However, prospective research on the specific effects of COVID-19 on sleep quality and rumination remains limited. The current study aims to fill this gap by investigating how the pandemic affects sleep quality and nighttime rumination in both adults and adolescents. It was hypothesised that COVID-19 would worsen sleep quality and increase nighttime rumination, particularly in adolescents. Methods: 101 participants (67 adults, 34 adolescents) were assessed using a within-betweensubjects design comparing two time periods (before and during COVID-19) across two age groups. Sleep quality was assessed daily by asking three questions that measured subjective sleep quality, sleep latency and wake after sleep onset. Nighttime rumination was quantified using self-reported rumination scores. Results: No significant differences in sleep quality or nighttime rumination were observed between the two periods for either age group. However, during the pandemic, adults experienced significantly worse sleep quality and increased nighttime rumination compared to adolescents. Additionally, nighttime rumination had a negative effect on sleep quality in both age groups. Conclusion: The study did not find statistically significant differences across time periods, but adults reported poorer sleep quality and higher levels of nighttime rumination during the pandemic compared to adolescents. These findings highlight the importance of further research to understand and address the psychological impact of global health crises in diverse populations.Show less
Adolescence is often characterized by an increase in negative affect and depressive symptoms. Sleep problems are common in depressed adolescents. Previous research indicates that sleep and mood are...Show moreAdolescence is often characterized by an increase in negative affect and depressive symptoms. Sleep problems are common in depressed adolescents. Previous research indicates that sleep and mood are bidirectionally associated. However, the predictive relationship between daily mood and sleep in the next night remains less clear. The current study aimed to compare subjective sleep quality between healthy and depressed adolescents. Secondly, this study aimed to examine whether the daily mood of the adolescents and parents, as well as parent-child interactions, predict sleep quality. A 14-day longitudinal observational study using ecological momentary assessment (EMA) was conducted in a sample of depressed (n = 80) and healthy adolescents (n = 35), aged between 11 and 17 years (M = 15.79, SD = 1.46), and their parents (n = 216). 65.6% of the participants were female and 34,4% were male. Participants completed four daily assessments on their mobile phones. The results indicate that adolescents with depression suffer from poorer sleep quality than healthy adolescents (MD = 1.60 (95% CI, 1.39 to 1.82), t(366.88) = 14.48, p < 0.001). Daily positive affect of the adolescent (b = 0.16, t(773.05) = 3.21, p < 0.001) and daily positive affect of the parents (b = 0.18, t(605.26) = 2.57, p = 0.01) were associated with better sleep quality of the adolescents. The effect of adolescent positive affect disappeared when controlling for other variables. Increasing positive affect during the day might consequently improve sleep quality. Interventions should consider the role of the family environment in adolescent sleep.Show less
Background: People with type 1 diabetes (T1D) often experience problems with their glucose regulation (glucose variability and glucose control), sleep quality, and cognitive functioning. However,...Show moreBackground: People with type 1 diabetes (T1D) often experience problems with their glucose regulation (glucose variability and glucose control), sleep quality, and cognitive functioning. However, their interrelation has not often been investigated. The aim of this study was to investigate how sleep quality and cognitive functioning are associated with glucose regulation in people with T1D. Method: Continuous glucose monitoring (CGM) data was collected over two weeks, in 18 participants, while each day subjective sleep quality (once in the morning) and cognitive functioning (e.g., ability to concentrate, finding words) (up to five times during the day) was measured using ecological momentary assessments (EMAs). Based on the CGM data, glycemic parameters (glucose variability and glucose control) during the night and day were calculated and a mean value of cognitive functioning per day was composed. Linear mixed model analyses were used to test for 1) whether sleep quality was influenced by glycemic parameters during the night and 2) whether cognitive functioning during the day was influenced by sleep quality and whether cognitive functioning was associated with glycemic parameters during the day. In addition, an interaction effect between sleep quality and glucose variability on cognitive functioning was explored. Lastly, visual plots were used to explore the associations on an individual level. Results: No statistically significant main effects were found for either association. However, an interaction trend (ß = -2.07, p = .070) between sleep quality and glucose variability on cognitive functioning scores was found. For days with normal fluctuations in glucose levels, better sleep quality was associated with better cognitive functioning, whereas for days with high glucose variability, this association could not be found. Regarding the individual plots, both, positive and negative relationships between all mentioned variables were apparent, exemplifying important inter-individual differences. Conclusion: For people with T1D, the relationships between glucose parameters, sleep quality, and cognitive functioning, vary from person to person. This finding advocates for looking at the individual level when implementing possible treatment methods for increasing sleep quality and cognitive functioning. More research in a larger sample is warranted to further examine the inter-individual factors in these associations.Show less
Background: Impairments in cognition are considered as one of the core features of psychotic disorders, including impairments in executive functioning (EF). EF is an umbrella term that incorporates...Show moreBackground: Impairments in cognition are considered as one of the core features of psychotic disorders, including impairments in executive functioning (EF). EF is an umbrella term that incorporates several higher cognitive functions. Findings on the relationship between substance use and EF are inconsistent. A potential mechanism underlying the effect of substance use on EF may be sleep disturbance. Therefore, the aim of this thesis study was to identify the relationship between substance use and EF in people diagnosed with a psychotic disorder and examine whether sleep quality mediates this relationship. Methods: The current sample comprised 301 participants with a primary diagnosis of a psychotic disorder. Schizophrenia was the most common diagnosis in the sample (43.2%). EF was assessed using the Behaviour Rating Inventory of Executive Function for Adults (BRIEF-A). Substance use was assessed using the Measurements in the Addictions for Triage and Evaluation questionnaire (MATE). Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Results: Results of a linear regression analysis showed a significant positive relationship between the MATE and BRIEF-A (β = .25, p < .001). The mediation analysis confirmed this significant positive relationship between the MATE and the BRIEF, by a significant total effect (β = .25, p = .001). The indirect effect of the MATE on the PSQI was not significant (β = -.0004, p = .996). The indirect effect of the PSQI on the BRIEF-A was significant (β = .22, p = .002). The direct effect of the MATE on the BRIEF-A was significant as well (β = .25, p < .001). Conclusion: Our findings suggest that more problematic substance use is associated with worse EF. This relationship is not mediated by sleep quality in our study, as substance use was not found to be associated with sleep quality. However, we found that better sleep quality was associated with better EF. These results highlight the importance of taking substance use and poorer sleep quality into account in the treatment of psychotic disorders.Show less
Quality sleep is paramount for the mental and physical health of university students and for their academic success. Stress was found to be a precipitator and a maintaining factor of poor sleep....Show moreQuality sleep is paramount for the mental and physical health of university students and for their academic success. Stress was found to be a precipitator and a maintaining factor of poor sleep. Moreover, vulnerabilities in the student population may maintain and/or exacerbate a possible association between stress and sleep quality; one of which is the development or the existence of poor coping strategies to deal with stress, such as a propensity to engage in perseverative negative cognitions (PNCs). This study examined whether an increase in academic stress was related to a decrease in the sleep quality of university students. Additionally, moderation by two different PNCs (i.e., excessive worry and rumination) were expected, with high levels of PNCs associated with an exacerbation of the relationship between academic stress and sleep quality. Lastly, the unique contribution of the two PNCs to the moderation effect was explored. Cross-sectional data from 49 university students were obtained using a series of questionnaires (Mage = 19.6 years, female = 95.9%). A simple regression analysis failed to indicate that an increase in academic stress predicts a decrease in sleep quality (p = .30). In addition, a hierarchical multiple regression failed to establish that PNCs moderate the relationship between academic stress and sleep quality (p = .18), suggesting that high levels of PNCs may not be associated with an exacerbation of the relationship. Furthermore, this study did not find evidence for the individual contribution of both types of PNCs to the moderation effect of PNCs in the association between academic stress and sleep quality (p = .28 for worry as a moderator; p = .47 for rumination as a moderator). These findings inform that academic stress might not share the same link with sleep difficulties as other types of stress have demonstrated. Furthermore, there is the possibility of additional concomitant difficulties (i.e., depression and anxiety) being relevant for the associations investigated, either as subsequent outcomes or as determinants of these associations. These findings provide a basis for future research on possible resistances experienced by this population and inform interventions that could help ameliorate sleep quality in university students.Show less
Greater perceived stress is associated with maladaptive repetitive thinking, which can be divided into worry and rumination. Previous literature found associations between rumination, stress, and...Show moreGreater perceived stress is associated with maladaptive repetitive thinking, which can be divided into worry and rumination. Previous literature found associations between rumination, stress, and sleep quality; however, for the subcomponents of rumination, namely brooding rumination and reflective pondering, only a relationship between brooding rumination and stress has been found in which brooding rumination increases after the occurrence of a stressor. In order to gain more insights into both the relationship of brooding rumination and sleep quality in moderation of academic stress in students, and to exploratively investigate the relationships between brooding rumination and reflective pondering with sleep quality, an online questionnaire using the Ruminative Response Scale, the Pittsburgh Sleep Quality Index, and the Perception of Academic Stress was used with Leiden university students. The hierarchical multiple linear regression with interaction did not find a moderation effect for academic stress on the relationship between brooding rumination and sleep quality with F(3, 43) = 0.98 p = .413, and both simple linear regressions revealed insignificant results for an association between brooding rumination and reflective pondering with sleep quality with F(1, 44) = 1.35 p = .252 and F(1, 44) = 0.06, p = .803, respectively. Whereas the latter finding may suggest an association of the subcomponents of rumination with sleep quality through the possible mediator depression, the former finding could be depicted in a simple slope analysis that suggested a moderation effect of academic stress after all. The clinical relevance of this study therefore lies on the moderation effect of academic stress and the relationships between rumination, sleep quality, and depression.Show less
Previous research suggests an association between attentional control and rumination, supported by the impaired disengagement hypothesis. According to the impaired disengagement hypothesis,...Show morePrevious research suggests an association between attentional control and rumination, supported by the impaired disengagement hypothesis. According to the impaired disengagement hypothesis, individuals with low attentional control are more likely to experience increased rumination due to difficulties in disengaging from negative thoughts. A relationship between rumination and poor sleep quality has also been previously investigated and the findings are in line with the concept of perseverative cognition. As illustrated by the concept of perseverative cognition, rumination has been associated with poor sleep quality because the cognitive arousal that accompanies rumination may lead to physiological arousal resulting in unsuitable conditions for quality sleep. However, the potential mediating role of rumination in the relationship between attentional control and sleep quality has not yet been fully elucidated. The primary aim of the current study was to investigate whether rumination significantly mediates the relationship between attentional control and sleep quality. I expected increased rumination to mediate the relationship between low attentional control and poor subjective sleep quality. 69 healthy university students completed questionnaires including measures of attentional control, rumination, and sleep quality. A mediation analysis and a bootstrap was employed to test the significance of the indirect effects. Results showed that rumination fully mediated that effects of attentional control on sleep quality. A bootstrap analysis confirmed the significance of the mediation model. Targeting attentional control and rumination may prove beneficial in treatments for poor sleep quality. Interventions such as mindfulness-based therapy have been successful in reducing rumination, whereas attentional training technique has shown promising results in improving attentional control.Show less
Benefits of sleep (e.g., mental health) and detrimental effects of sleep-loss (e.g., impaired academic performance) have been extensively researched and implications are broad. A considerable...Show moreBenefits of sleep (e.g., mental health) and detrimental effects of sleep-loss (e.g., impaired academic performance) have been extensively researched and implications are broad. A considerable amount of research on the relations between perfectionism and sleep exists, where perfectionism negatively affects sleep quality. Mediators, primarily anxiety, affecting sleep quality have been investigated as well. However, within the bounds of conducted literature search, research with a mediatory model of maladaptive repetitive thinking (MRT) on perfectionism and sleep quality in a student population seems to require further exploration. Therefore, current work investigated whether MRT (i.e., worry and rumination) mediates the relationship between perfectionism and sleep quality. Data was analyzed from an overarching main study which, through convenience sampling, recruited 69 healthy university students who filled in online questionnaires (e.g., assessing rumination and sleep quality). In line with previous research, results showed that increased perfectionism was related to worse sleep quality and increased maladaptive repetitive thinking. Furthermore, increases in maladaptive repetitive thinking was related to worse sleep quality. However, the proposed mediation was found to be nonsignificant. Several limitations were at play (e.g., self-report measurements), thus it is recommended to replicate the current work and minimize these limitations. As sleep has a wide array of implications on healthy overall functioning it is recommended to explore the triad further, paving the way to innovations to improve sleep quality and consequently healthy functioning in the student population.Show less
Challenges in stress management, effective attention direction, and striving for adequate sleep are reflected in a student’s life and academic performance. According to recent research, decreased...Show moreChallenges in stress management, effective attention direction, and striving for adequate sleep are reflected in a student’s life and academic performance. According to recent research, decreased attentional control is related to an increased tendency to engage in maladaptive repetitive thinking (RT) i.e., rumination and worry, which has been considered as a threat to sleep quality. Furthermore, an increase in academic stress has been found to impair students' sleep quality. Using moderation analysis, the current study investigated whether maladaptive RT strengthened the relationship between academic stress and sleep quality. We used linear regression analysis (LRA) to investigate the relationship between attentional control and maladaptive RT. A number of self- report questionnaires were used in this cross-sectional study to measure attentional control, sleep quality, academic stress, worry, and rumination. The final sample consisted of 50 Leiden University students aged 17-30 years. The results of the simple LRA showed that poor attentional control is related to a higher tendency of maladaptive RT, such as rumination and worry. The result of the moderation analysis revealed that neither rumination (b = -.001, t = -0.90, p = .930) nor worry (b = - .003, t = -0.73, p = .471) strengthened the relationship between increased academic stress and poor sleep quality. Despite its limitations, the study serves as a preliminary study into the role of rumination and worry in the relationship between academic stress and sleep quality and provides methodological suggestions for future research to yield more reliable results.Show less
Research findings on the interrelationships between stress and sleep, stress and optimism, optimism and sleep have been found in the literature. However, a possible relationship between all three...Show moreResearch findings on the interrelationships between stress and sleep, stress and optimism, optimism and sleep have been found in the literature. However, a possible relationship between all three of these variables together remains unstudied. Understanding this relationship and whether these relationships are interdependent, may provide new prevention and intervention opportunities for sleep- or stress-related health problems. The current study aimed to investigate whether the relationship between perceived stress and sleep quality depends on the level of optimism. The study employed a quantitative and quasi experimental design, with data collected cross-sectionally via online self-report questionnaires. The Life Orientation Test Revised was administered to measure the level of optimism, the Perceived Stress Scale was administered to measure the level of stress, and the Pittsburgh Sleep Quality Index was administered to assess sleep quality. To examine the hypothesis that the level of optimism will moderate the relationship between level of perceived stress and sleep quality, a moderated hierarchical multiple linear regression analysis was conducted on data from 250 respondents. The results revealed that the level of perceived stress was able to predict sleep quality (b = .14, p < .001), but the level of optimism failed to predict sleep quality (b = -.05, p > .05) and no evidence was found for the moderating role of optimism in the relationship between perceived stress and sleep quality (b = .002, p > .05). It is possible that the baseline sleep quality was not poor enough, and there were not enough people with low levels of optimism to detect whether the level of optimism could interfere with the relationship between perceived stress and sleep quality. However, the role of optimism within this relationship can be studied more in the future, with better-informed research designs.Show less
In this study the effects of using blue-light filter glasses on sleep quality and vigilance is investigated in 60 young adults, in order to gain more insight in blue-light filter glasses as an...Show moreIn this study the effects of using blue-light filter glasses on sleep quality and vigilance is investigated in 60 young adults, in order to gain more insight in blue-light filter glasses as an effective aid for poor sleep quality. Blue-light filter glasses were expected to have a positive effect on sleep quality and vigilance performance. This was a single-blind controlled study in which the participants reported their sleep quality on the PSQI and KSS and their vigilance performance was measured with the Psychomotor Vigilance Task. After two weeks of intervention, wearing blue-light filter glasses in the experimental condition and listening to music in the control condition, follow-up measures were registered. Measures of total sleep quality and sleep latency increased and vigilance reaction times decreased over time in the analysis of variances with repeated measures. These changes could not be explained by the use of blue-light filter glasses or the relation between vigilance and sleep quality. The expected positive relation between sleep quality and cognitive performance was not supported by these findings. In conclusion, this study does not provide convincing support for blue-light filter glasses as an effective aid for poor sleep quality. Among others, including objective measures and treatments with longer periods of time are recommended for future research.Show less
Objective: The present study aims to better understand possible multidirectional interactions between depressive symptoms, sleep quality and stress response. Although a significant amount of...Show moreObjective: The present study aims to better understand possible multidirectional interactions between depressive symptoms, sleep quality and stress response. Although a significant amount of research has been done studying the effect of sleep quality and depression on stress response, they provided mixed results and showed large methodological differences. We extend previous research by testing three hypotheses: (a) Poor sleep leads to increased stress responses; (b) Higher levels of depressive symptoms lead to increased stress responses; and (c) The effect of minimal levels of depressive symptoms on stress reactivity is greater for individuals with poor sleep. Method: In 46 participants (69,60% female; 18–29 years), we assessed sleep quality using the Pittsburgh Sleep Quality Index (and depressive symptoms using the Hospital Anxiety and Depression Scale (HADS). The Trier Social Stress Test (TSST), a psychosocial stress task, was used to induce moderate stress in a controlled environment in order to assess stress reaction. Results: Participants with poorer sleep quality did not have elevated salivary cortisol response after being exposed to a social stressor compared to participants with better sleep quality. Also, no proof was found for (minimal) depressive symptoms being a predictor of salivary cortisol response to psychosocial stress. The results further indicated that individuals with poor sleep quality did not experience a greater effect of (minimal) depressive symptoms on stress reactivity. Conclusion: No support was found for a role of sleep quality and depressive symptoms in cortisol stress response. Future research should take person- and situation-specific characteristics into account when analyzing cortisol responses to psychological stress.Show less
Multiple studies suggest that worse sleep quality would lead to a worse mood the next day. It is important to address this issue, because mood is an essential factor regarding someone’s quality of...Show moreMultiple studies suggest that worse sleep quality would lead to a worse mood the next day. It is important to address this issue, because mood is an essential factor regarding someone’s quality of life. However, it is not clear how this works for children. Another issue that comes forward is that it is unclear how gender moderates this relationship. We investigated the moderating effect of gender on the relationship between sleep quality and mood in 82 normally developing children (Age M= 7.44; SD=.61; age range 7-9; 43% boys). Sleep quality was defined as sleep efficiency and was measured with actigraph watches the children wore at night. Parents filled in diary questions about their children’s affective mood states: valence, energetic arousal and calmness. We looked at the influence of one night of sleep on mood the next day. We did not find a relationship between sleep efficiency and mood. This shows that mood in normal developing children is not affected by sleep efficiency. We also researched if gender moderates the relationship between sleep efficiency and mood. The effect of sleep efficiency and mood was the same for boys and girls. This finding strengthens the idea that gender differences only become apparent after the onset of puberty. Therefore it does not matter if you are a boy or a girl: one bad night of sleep will not affect your mood the next day.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
under embargo until 2035-11-28
2035-11-28T00:00:00Z
The aim of this study was to examine whether routines around bedtime mediate the relation between family disorganization and sleep quality. In addition, we explored the moderating role of child...Show moreThe aim of this study was to examine whether routines around bedtime mediate the relation between family disorganization and sleep quality. In addition, we explored the moderating role of child temperament in the relation between bedtime routines and sleep. A moderated mediation model was tested in 52 families with a three to four year old twin. We randomized the two children within the families to create two comparable samples and tested the model in both samples. Parents reported on family disorganization, child temperament, and the child´s bedtime routines and bedtimes. Actigraphy was used to assess sleep duration and sleep onset latency. No associations were found between family disorganization and sleep. Consistent bedtime routines but not consistency in bedtimes itself significantly predicted sleep quality in one of the samples. The relation between bedtime routines and sleep quality was moderated by child characteristics: Children with low levels of self-regulation have lower sleep quality when there are inconsistent routines around bedtime. These findings suggest that implementing a consistent routine around bedtime may be particularly important for children with low levels of self-regulation.Show less
