Rui-Wen Song,Yi-Jun Zhang,Hui-Qiang Zhao,Li-Ping Zhang*

1School of Management of Tianjin University of Traditional Chinese Medicine,Tianjin,China.

#These authors contributed equally to this work.

Abstract

Keywords: Mindfulness, Sleep quality, Mindfulness cognitive level, Pittsburgh sleep quality index, Five facet mindfulness questionnaire

Background

Sleep is an important part of life activities and an important link for the body to recover, integrate, and consolidate the memory. A good sleep is an important basis for maintaining the physical and mental health, as well as the complete social functions of an individual [1].Long-term sleep problems decrease the cognitive function and vitality and are associated with stress, anxiety, depression, mental disorder,physical illness, and a high risk of suicide [2]. Available studies have shown that about 18.7%-21.4% of Chinese college students are troubled with sleep problems, which are manifested by difficulty falling asleep, waking up too early, insufficient sleep, low sleep efficiency, or low daytime energy level [3-4]. Therefore, it has become an urgent problem to explore the effective intervention method that improves the sleep quality and to investigate the psychological mechanism that affects the sleep quality of college students [5-6].Studies have found that the mindfulness cognitive level is positively correlated with the sleep quality [7-8], and the use of mindfulness-based cognitive therapy (MBCT) can effectively improve the sleep problems of depressive college students [9-10]. In previous studies, most of the interventions were conducted in subjects with sleep disorders or negative psychological states, and few studies focused on the population who were troubled with sleep problems but had not yet reached the clinical diagnostic criteria for sleep disorders.Therefore, this study was designed to explore the intervention effect of MBCT on the sleep quality of college students who scored below the critical value of sleep disorders. Furthermore, this study was also designed to provide a feasible method for improving the sleep quality of college students and to provide a scientific basis for promoting mental health in colleges and universities.

Subjects and methods

Subjects

A total of 290 freshmen who volunteered for the mindfulness-based training were recruited from Donghua University in Shanghai from September to December 2020. ① Inclusion criteria included a total Pittsburgh Sleep Quality Index (PSQI) score ＜7.5 points and a component score of sleep quality ≤1 point, assessed by PSQI and screened by interview before the enrollment. ② Exclusion criteria included the following: (1) presence of psychological disorders or sleep problems due to physical sickness or psychological disorders(such as depression and anxiety); (2) use of sleeping medication in the past 3 months; (3) having mindfulness-related practice in the past 1 year; (4) insomnia caused by use of alcohol, coffee, tea, and other stimulating beverages; and (5) use of psychotropic drugs. A total of 70 subjects were included in this study. They were divided into the experimental group (n = 35) with 22 males and 13 females and the control group (n = 35). The subjects in both groups had signed the informed consent form. This study follows the principles of confidentiality and voluntariness to protect the privacy of subjects,and the study has been approved by the ethics committee of Tianjin University of traditional Chinese medicine.

Methods

No measures were taken for the control group. The MBCT was performed in the experimental group according to “The Mindful Way Workbook: An 8-Week Program to Free Yourself from Depression and Emotional Distress” [11] to train all subjects together, including the related concepts, intervention methods, operating skills, and precautions of the MBCT. The training was carried out for 1 hour,followed by half an hour of optional free communication, on each day from Monday to Friday. The schedule for the 8-week mindfulness-based training is shown in Table 1. Subjects in the two groups were evaluated both before intervention and after the 8-week intervention by the PSQI and Five Facet Mindfulness Questionnaire(FFMQ).

Observation indexes and evaluation criteria

Sleep quality was assessed with the PSQI [12]. The PSQI contains 19 self-rated items, which combined 6 components as follows: sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance, and daytime dysfunction. Each component is scored in a range of 0-3 points, and the sum of the scores of the 6 components yields one total PSQI score. The lower score indicates better sleep quality. The Cronbach’s α of the PSQI was 0.67.

The mindfulness cognitive level was evaluated with the FFMQ [13].The FFMQ contains 39 items, which combined 5 subscales as follows:observing, describing, acting with awareness, nonjudging of inner experience, and nonreactivity to inner experience. The items of the FFMQ are rated on a 5-point Likert scale. The subscale scores are added to yield one total FFMQ score.The higher score indicates higher mindfulness cognitive level. The Cronbach’s α of the FFMQ was 0.93.

Statistical methods

Data were processed with SPSS 17.0. The normality test showed that the measurement data (PSQI and FFMQ scores) conformed to the normal distribution, so they were statistically described by mean ±standard deviation. The differences between the groups were analyzed with t-test. The count data were expressed by percentages, difference analysis was made with the χ2test, and P ＜0.05 was considered statistically significant.

Results

General data

A total of 70 subjects were enrolled based on the inclusion/exclusion criteria. There were 22 male and 13 female students in the experimental group; furthermore, there were 25 male and 10 female students in the control group. No statistical difference was noted between the two groups in gender and place of domicile (P ＞0.05),as shown in Table 2. The changes in sleep quality and mindfulness cognitive level in the experimental group and control group before and after intervention are shown in Table 3. Before intervention, there was no significant difference found between the two groups in the total PSQI score or any component score (P＞ 0.05). After intervention, the score differences before and after intervention were compared between the two groups. The results revealed that the total PSQI score and the 3 component scores of sleep quality, sleep duration, and sleep disturbance in the experimental group were significantly lower than those in the control group. The differences were statistically significant (P＜0.05), as shown in Table 3.

Before intervention, there was no significant difference found between the two groups in the total FFMQ score or any subscale score(AllP＞0.05). After intervention, the score differences before and after intervention were compared between the two groups. The results revealed that the total FFMQ score and the score of nonreact in the experimental group were significantly lower than those in the control group. The differences were statistically significant (P＜0.05), as shown in Table 4.

The changes in sleep quality and mindfulness cognitive level scores in the experimental group before and after intervention are shown in

Table 5 and Table 6. The paired samples t-test was conducted to each component score of the PSQI of the subjects in the experimental group which are assessed before and after the intervention. The results revealed significant differences in the scores of sleep quality, sleep latency, sleep duration, sleep disturbance and daytime dysfunction.The differences in the total PSQI score(P＜0.05) is shown in Table 5.The paired samples t-test was conducted to each subscale score of the FFMQ of the subjects in the experimental group measured before and after intervention. The results revealed significant differences in the score of observing, nonreacting and the total FFMQ score (AllP＜0.05), as shown in Table 6.

Table 1 Schedule for the 8-week mindfulness-based training

Table 2 Baseline characteristics of the enrolled students

Table 3 Comparison of PSQI scores before and after intervention between the experimental group and control group(M± SD)

Table 4 Comparison of FFMQ scores before and after intervention between the experimental group and control group(M±SD)

Table 5 Comparison of PSQI scores before and after intervention in experimental group（M± SD,n=35）

Table 6 Comparison of FFMQ scores before and after intervention in experimental group (M±SD)

Discussion

The MBCT combines cognitive therapy and mindfulness-based training, focuses on training people’s attention, and mainly teaches people to change their cognition, accept the current consciousness without placing any judgments upon it, and maintain a peaceful state of mind, so as to change emotions and body sensations [14-15].Relevant studies have shown that MBCT has a good intervention effect on insomnia [16].

Our study confirmed that after intervention by mindfulness-based training, the total PSQI score and component scores of sleep quality,sleep duration, and sleep disturbance in the experimental group were improved, compared with those in the control group, while the total PSQI score and the component scores of sleep quality, sleep latency,sleep duration, sleep disturbance and daytime dysfunction in the experimental group were significantly improved after intervention compared with those before intervention. This indicates that that sleep quality of subjects in the experimental group was significantly improved after 8 weeks of mindfulness-based training.The total FFMQ score and the subscale score of nonreacting in the experimental group were improved, compared with those in the control group; while the total FFMQ score and the subscale score of observing and nonreacting in the experimental group were significantly improved after intervention compared with those before intervention, indicating that the mindfulness cognitive level of the college students was significantly improved.

The subjects of this study were college freshmen. Facing changes of the living environment, heavy academic pressure, and maladaptation to interpersonal relationships, freshmen are likely to experience emotional fluctuations, leading to changes of sleep quality [4]. Liu Wei, et al. [17] performed MBCT and effectively improved the sleep quality of college students with the predisposition to depression. In this study, an 8-week MBCT was performed, which enhanced the mindfulness cognitive level of the students, taught them to adopt a“nonjudging” attitude to the emotions and events that bothered them,reduced their perceived stress[18],and made them feel calm[19] and focus more on sleep. As a result, the sleep latency was shortened, the effective sleep duration was prolonged [20], a good psychological state was maintained [21], and the sleep problems were thereby solved.

Conclusion

The 8-week mindfulness-based cognitive training had a significant effect on improving the sleep quality of the college students who scored below the critical value of sleep disorders. This improvement may have been achieved by enhancing the mindfulness cognitive level of these students.