Effectiveness of Mindfulness-Based Stress Reduction on Mental Health and Psychological Quality of Life among University Students: A GRADE-Assessed Systematic Review

Background Psychological distress is a progressive health problem that has been linked to decreased quality of life among university students. This meta-analysis reviews existing randomized controlled trials (RCTs) that have examined the effects of mindfulness-based stress reduction (MBSR) on the relief of psychosomatic stress-related outcomes and quality of life among university students. Methods The PubMed, EMBASE, Web of Science, PsycINFO (formerly PsychLit), Ovid MEDLINE, ERIC, Scopus, Google Scholar, ProQuest, and Cochrane Library databases were searched in November 2023 to identify the RCTs for analysis. Data on pathology (anxiety, depression, and perceived stress), physical capacity (sleep quality and physical health), and well-being (mindfulness, self-kindness, social function, and subjective well-being) were analyzed. Results Of the 276 articles retrieved, 29 met the inclusion criteria. Compared with control therapies, the pooled results suggested that MBSR had significant effects, reducing anxiety (SMD = −0.29; 95% CI: −0.49 to −0.09), depression (SMD = −0.32; 95% CI: −0.62 to −0.02), and perceived stress (SMD = −0.41; 95% CI: −0.60 to −0.29) and improving mindfulness (SMD = 0.34; 95% CI: 0.08 to 0.59), self-kindness (SMD = 0.57; 95% CI: 0.30 to 1.12), and physical health (SMD = −0.59; 95% CI: −1.14 to −0.04). No significant differences were observed in sleep quality (SMD = −0.20; 95% CI: −0.06 to 0.20), social function (SMD = −0.71; 95% CI: −2.40 to 0.97), or subjective well-being (SMD = 0.07; 95% CI: −0.18 to 0.32). The quality of the evidence regarding sleep quality and physical health outcomes was low. Conclusions MBSR therapy appears to be potentially useful in relieving functional emotional disorders. However, additional evidence-based large-sample trials are required to definitively determine the forms of mindfulness-based therapy that may be effective in this context and ensure that the benefits obtained are ongoing. Future studies should investigate more personalized approaches involving interventions that are tailored to various barriers and students' clinical characteristics. To optimize the effects of such interventions, they should be developed and evaluated using various designs such as the multiphase optimization strategy, which allows for the identification and tailoring of the most valuable intervention components.


Introduction
Mindfulness therapy is a standardized psychological intervention that aims to reduce stress, encourage mindful thinking habits, and allow recipients to manage difcult emotional processing.It focuses on the concentration of one's attention in the moment, nonsubjective judgment, and openness to accepting personal experience and involves corresponding behavioral training, such as attention training, body scanning, and sitting meditation [1].Previous research on psychological interventions has found that mindfulness therapy can help reduce stress among university students and afects their overall quality of life and the psychological functions to which they adapt [2].
Te theoretical support and the understanding of the operating mode are reasonable but still have diferences.Tus, the mental health benefts, potential efects, and limitations of mindfulness therapy for university students warrant further examination.Although education and social support can be efective in preventing and treating the underlying psychological problems among university students with poor mental health, such interventions do not always afect or improve psychological well-being [3,4].
Te most prevalent psychological symptoms among university students are anxiety, mental stress, and emotional distress, which can result in decreased functioning in the context of academic and interpersonal stress.Global mental health surveys conducted by the World Health Organization (WHO) indicate that mental disorders are highly prevalent among university students, with 12-month prevalence rates ranging from 20.3% to 45% of university students over the age of 18 [5][6][7].Te prevalence rates of insomnia, depressive symptoms, and anxiety symptoms were 37.80%, 48.20%, and 36.70%,respectively, among Chinese university students during the COVID-19 pandemic [8].In a randomized controlled trial with 11,169 university students conducted by the WHO, students had increasing intentions to use mental health services: Te results indicated lifetime use rates of 12.6% and 7.3% for psychotherapy and medication for emotional problems, respectively.Suicidal thoughts and behaviors and nonsuicidal self-injury within the preceding 12 months were also common, with 21.1% of students in the sample reporting suicidal ideation, 10.6% reporting suicide plans, 0.4% reporting suicide attempts, and 6.8% reporting nonsuicidal self-injury [5].Furthermore, one previous study found that high-compliance mental health services had a signifcant efect on students' intention to seek mental health services in the next semester [9][10][11].
Evidence indicates that mindfulness therapy can result in a signifcant reduction in burnout, distress, anxiety, depression, and stress and a signifcant improvement in life satisfaction, positive afect, gratitude, self-compassion, and mindfulness among university students [12,13].However, although some studies show that mindfulness-based stress reduction (MBSR) can help relieve psychological symptoms and improve quality of life among university students, there is no reliable evidence that this type of intervention can help prevent or treat psychological abnormalities and, thereby, improve university students' subjective well-being.In addition, there are disparities between consensus-based conclusions regarding MBSR and clinical recommendations.
Some studies have used evidence-based medicine approaches to examine the efects of MBSR treatment on university students' psychological conditions.A recent study revealed that an MBSR intervention group showed statistically signifcantly fewer symptoms of stress and distress and had higher mindfulness than the control group.Previous studies of MBSR have emphasized its potential benefts for university students, such as minimizing perceived stress, preserving emotional stability, enhancing social functioning, and increasing the self-attractiveness of the group [14][15][16][17].Tis study adopted the Cochrane systematic review method to assess the efect of psychological interventions and the overall impact of MBSR treatment on the psychological condition of university students, aiming to provide a scientifc basis for the clinical practice of MBSR treatment.Our systematic review aimed to assess and renovate the available objective evidence on the efectiveness of MBSR in improving anxiety, depression, perceived stress, sleep quality, mindfulness, self-kindness, social function, subjective wellbeing, and physical health among university students.Te research was not registered in the International Prospective Registry of Systematic Reviews (PROSPERO).

Methods
2.1.Eligibility Criteria.Randomized controlled trials (RCTs) relating to mindfulness and stress reduction were included in this study.Te included RCTs were limited to those published in English and that met the following criteria: (1) Participants were aged 18 years or older and (2) participants were university students who were enrolled in higher education institutions at the time of the trial.In the included studies, participants took part in the experiments voluntarily and met the criteria for either an MBSR intervention group or a control group (wait-list, no treatment, health education, and relaxation, etc.).Te primary outcome index in the included RCTs included mental health problems and related outcomes that are common among university students (perceived stress, negative emotion, mindfulness, selfkindness, social function, subjective well-being, sleep problems, etc.).Te secondary outcome index was physical well-being.
Te exclusion criteria were as follows: (1) Participants were not registered university students; (2) their bodily functions could not handle MBSR therapy; (3) participants were diagnosed with mental disorders according to the classifcation of mental disorders, such as schizophrenia, major depression, panic disorders, or personality disorder; (4) participants were currently using psychoactive medication; (5) participants were currently undergoing individual psychotherapy or group intervention programs; and (6) participants sufered from cardiovascular diseases such as hypertension or arrhythmia.Participants were also excluded if they underwent any type of therapy or coaching during the study period.  1 at the end of this manuscript for details).

Study Selection.
Duplicate results were removed, and abstracts were screened using NoteExpress (v.3.9).Two reviewers independently selected and agreed upon the abstracts to be excluded.Two of the authors reviewed the full texts of the included abstracts and discussed and agreed upon their eligibility decisions.Eligible studies addressed the benefcial stress relief and mental health outcomes of MBSR interventions among university students.Following this procedure, the selection process was conducted independently by two other authors, and any disagreements were discussed with a third reviewer if necessary.Te data were extracted from the included studies, following the PRISMA checklist.Tese data mainly comprised the basic characteristics of the studies, characteristics of the study populations (sample size, age, and type of university student), intervention measures (type and specifc protocol of the MBSR intervention, duration, and frequency), control measures, and outcome indicators.When the outcome indicators were described by the median and interquartile interval, they were converted to means and standard deviations as per the quantile estimation method.

Data Abstraction and Assessment of the Risk of Bias.
A systematic review was performed following the Cochrane Handbook version 5.2.0 [18].Tree reviewers independently extracted the following information regarding each RCT: author name, publication time, mean age of participants, sample size, basic treatment regimen, control group settings, and outcome measures.Te quality of the included studies was evaluated using the risk bias assessment tool provided by the Cochrane Collaboration [19].Tree reviewers independently assessed the methodological quality of the included studies.Two investigators then cross-checked the information, and any disagreements were resolved with a third party.Te risk of publication bias across the included studies was examined using a funnel plot [20].Te systematic review and meta-analysis reporting were carried out in accordance with the PRISMA guidelines [21].
2.5.Data Analysis.Data were recorded using Excel 2010, and Stata software (version 10.0) was used for data processing.Statistical analysis was performed on the extracted data using standardized mean diferences (SMDs).Te efect sizes were expressed as 95% confdence intervals, and the test level wasα � 0.05.Meta-analysis statistical models were weighted according to the combined efect size.A chi-square test was conducted to analyze heterogeneity, and I 2 was used to evaluate the magnitude of heterogeneity.When I 2 < 50%, a fxed-efects model was used to estimate the combined efect size.If I 2 > 50%, the possible sources of heterogeneity were analyzed, and if the source of heterogeneity remained unidentifed and unaddressed, a random-efects model was used to estimate the combined efect size.Te outcome indicators of the included studies were combined for efect size analysis, 95% confdence intervals of the overall parameters were employed for estimation, and the U test hypothesis was used.p < 0.05 indicated that the diference in the combined efect size of the included studies was statistically signifcant.Te meta-analysis forest plot was performed using Stata (version 10.0, Stata Corp., College Station, TX, USA) [22] and Review Manager (RevMan, version 5.3) [19].

Grading of the Evidence. Te international Grading of
Recommendations, Assessment, Development, and Evaluation (GRADE) tool (GRADEpro GDT software, McMaster University, Canada, 2015) [23] was employed to assess the quality of evidence for the outcome indicators in the included studies.According to this tool, four factors can reduce the quality of the evidence presented: study limitations, inconsistent fndings, indirect fndings, and imprecise fndings.Te quality of the evidence presented in all the RCTs included in the present study was evaluated as moderate or high.

Description of Studies.
A total of 276 studies items were initially obtained through the database search.Using NoteExpress, 193 deduplicated studies were obtained, and the remaining 220 items were obtained.After reviewing their titles and abstracts, 135 studies that were of incompatible research types were excluded.A total of 13 articles were further excluded after reading the full text, and the remaining 29 studies  were retained for data extraction.Te baselines of the trials were comparable.Te literature search process and results are shown in Figure 1.
Te intensities of the MBSR protocols of the RCTs varied, ranging from twice weekly for 20 min to 1.5 hours each.Treatment durations ranged from 2 to 10 weeks.MBSR prescriptions difered depending on session timeline, content, and frequency.Indications of MBSR mainly focused on mood regulation and an increase in participants' levels of satisfaction with their quality of life, self-acceptance, social function, subjective well-being, physical health, and sleep quality (Tables 2 and 3).Evidence-Based Complementary and Alternative Medicine
Heterogeneity was present in the comparison of studies on anxiety (I 2 � 72.4%), depression (I 2 � 86%), perceived stress (I 2 � 70.7%), sleep quality (I 2 � 63.4%), mindfulness (I 2 � 80.5%), self-kindness (I 2 � 93.2%), social function (I 2 � 98.1%), subjective well-being (I 2 � 78.5%), and physical health (I 2 � 86%).A meta-regression revealed that the efects of age, inclusion criteria, indications, and duration did not explain this heterogeneity.Te meta-regression results showed that the efect of the duration of the MBSR therapy on anxiety (p ≤ 0.02), perceived stress (p ≤ 0.01), and subjective well-being (p ≤ 0.001) and the efect of the type of control group on depression (p ≤ 0.01) partly explained the heterogeneity.Age, recruitment, MBSR duration, control group, and the regional diferences of participants were not           Evidence-Based Complementary and Alternative Medicine the sources of heterogeneity for the efects on sleep quality, mindfulness, self-kindness, social function, and physical health (all p ≥ 0.05) (Table 5).Further subgroup analyses were conducted to examine the efect of diferent control groups (no treatment, health education, and social support) on depression.Subgroup analyses were also conducted to examine the efect of MBSR duration (less than 2 weeks, 4-6 weeks, and over 8 weeks) on anxiety, perceived stress, and subjective well-being (Figure 4).

GRADE Assessment.
Te quality of the evidence presented in the reviewed studies was assessed with the GRADEpro GDT software tool.Table 3 shows a summary of the overall assessment of the quality of evidence regarding

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Evidence-Based Complementary and Alternative Medicine Confdence in estimates of efect is poor, small sample size, and SRCTs do not calculate the optimal information size.4 Small sample and asymmetry of the funnel plot.
Evidence-Based Complementary and Alternative Medicine

Discussion
Mindfulness decompression interventions are considered one of the most popular forms of psychological intervention [54].Well-designed related studies on the efcacy of mindfulness for mental disorders have been conducted since Dr. Jon Kabat-Zinn founded mindfulness decompression therapy in 1982 [55].Mindfulness decompression therapy continues to be gradually recognized in an increasing number of professional felds [56,57].In this type of therapy, participants are guided to refect on their personality and mental tendencies and release internal conficts and stressors.Participants also explore the potential of selforientation in order to achieve meditation and intellectual fow, stabilize and adjust their emotions, reduce or eliminate negative feelings, and achieve a mild healing efect through physical and mental balance [58].
Existing research generally recognizes that mindfulness decompression psychological interventions can promote communication, enhance individual self-esteem, relieve emotions, and improve behavior.However, it is difcult to quantify the efect of such interventions; thus, this represents an important direction for researchers in related felds as they continue to expand the evidence base supporting mindfulness decompression interventions [59,60].
Our meta-analysis showed that there was heterogeneity between groups in relation to the efects of the duration of MBSR therapy on anxiety, depression, perceived stress, and subjective well-being.In our meta-analysis and systematic review, the subgroup analysis demonstrated that timed MBSR therapy intervention protocols had clear benefts for anxiety, depression, and perceived stress.Te subgroup analysis also revealed a linear relationship between the duration of the intervention and antinegative emotions and improved self-positive acceptance concepts, suggesting that relatively short interventions (e.g., two weeks) had a potential impact on the management of negative emotions and bufered stress.As long as the psychological intervention of mindfulness therapy was prescribed, the intervention of the study participants was efective.Due to its design, the current study could not determine the results of subsequent long-term follow-up.
Te subgroup analysis of depression control groups showed that the degree of remission of depressive symptoms in the no-treatment control group was signifcantly lower than that in the support and health education control groups.In the subgroup analyses of the efects of interventions on anxiety, perceived stress, and mindfulness, diferent intervention durations showed a mild improvement efect.MBSR attaches importance to an individual's physical condition, fexibility, and perception of physical and mental activities and attaches more importance to the adjustment and adaptation of their overall function.Tese factors refect the difculty and complexity of MBSR research, while also presenting opportunities and challenges for the integration of general practice via the existing MBSR research methodology.
Te subgroup analysis also revealed that the efects of MBSR interventions on depression outcome indicators were sensitive to the type of control group.As the MBSR intervention had a minimal impact on students in the control groups, it may be that the type of control group afected the initial positive fndings.
Te evaluation of the efect size of the control groups in the RCTs included in this review highlighted that when there was an imbalance in the baseline of control participants, the statistical data may be unstable, masked, or magnifed.Each MBSR RCT adopted a diferent study design and implemented control groups diferently.For some variables, the choice of the control group had far more infuence than the MBSR protocol on the research outcomes: Tis defciency was partly due to the design of the control groups.
Te meta-regression showed that there was heterogeneity between the length of the MBSR intervention and the control group, and the subgroup analysis showed that whether the efect of MBSR was pronounced or not was closely related to the duration of MBSR and the control groups.Practice heterogeneity and methodological heterogeneity are the main sources of heterogeneity in metaanalyses.Consequently, appropriate interpretation and analysis methods must be adopted to ensure the reliability of meta-analysis results.
Te prevalence of physical function and sleep problems among university students is relatively high, and sleep problems tend to last for years after the end of treatment [61,62].University students' psychological and social adaptation difculties may refect the negative consequences of poor physical health and sleep quality.Previous studies have revealed that more than half (52.7%) of university students sleep 6 to 8 hours per night, 37% sleep less than 6 hours, and 40% go to sleep after 2 am [63][64][65].Our meta-analysis observed no signifcant diference in improvement in sleep disorders following MBSR interventions.Te included studies evaluated sleep quality after intervention and at 4-12 weeks postintervention.In the studies on sleep quality in our meta-analysis, the average follow-up time was 6.67 weeks, which was likely not long enough.Future RCTs examining the efects of MBSR intervention on sleep quality and physical health should standardize follow-up times and aim to establish the content validity of the domains of sleep quality and physical health that are assessed.
Our meta-analysis suggests that mindfulness decompression psychological intervention is conducive to the psychological and behavioral health of university students.Te positive results of this type of intervention are manifested in the release of negative emotions, such as anxiety, depression, and perceived stress.MBSR interventions also show a positive efect on the establishment of self-confdence among university students.Te blinding of participants, personnel, and outcome assessors was performed in most studies in our meta-analysis and systematic evaluation.However, defects in these studies' research methods limit the interpretation of the efectiveness of these fndings.Te sample sizes of the eligible studies were small, and their methods of estimating these sample sizes were unclear.Globally, there is an overall lack of high-quality random comparison studies of MBSR interventions involving university students.

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Evidence-Based Complementary and Alternative Medicine Not all the included studies adopted the standard design of mindfulness decompression psychological intervention programs.Tey also did not all describe (1) whether the implementer had received professional mindfulness decompression psychological intervention training; (2) the professional knowledge of the mindfulness decompression psychological intervention practitioners; or (3) the frequency, intensity, content, or duration of the mindfulness decompression psychological intervention.Furthermore, the settings of the control groups and the heterogeneity of the basic physical and sociological characteristics of the university student participants afect the reliability of the conclusions drawn in these studies.Such inconsistencies and imprecision were major reasons for downgrading the accuracy and quality of the evidence recommending the use of MBSR therapy in research involving university students.Tey also show underlying insignifcant psychological efcacy.
Tere were further serious concerns related to four GRADE domains (risk of bias, inconsistency, indirectness, and imprecision) across the three studies that measured MBSR.As such, the certainty of the evidence that MBSR promotes well-being through improved sleep quality was very low.We identifed 29 studies that employed a range of mindfulness meditation methods, of which all but nine were published within the past decade.Nevertheless, there were relative consistency concerns related to two or more GRADE domains (risk of bias, inconsistency, and indirectness or imprecision) across the studies, implying a moderate certainty in the evidence that MBSR reduces psychological distress and promotes well-being among university students.
In addition, the results indicate that it is important that the mental health gains generated by mindfulness stress reduction practices among college students are sustained over time.After some time, students may become more aware of the improvements in their well-being and mental health owing to MBSR interventions-they will feel better about themselves and realize that improvements in their physical health, stress levels, and well-being were gained through meditation training.Tus, though the efects of MBSR training can be validated immediately after an intervention, they may not yet be consolidated to the point that recipients consciously recognize all of these efects.Te efects of meditation practice are gentle, accumulate slowly, and become more pronounced over time as students practice what they have learned.Furthermore, among university students, medical students tend to better perceive the benefts of training when exposed to stressful situations.When the knowledge learned in training can be put into practice in challenging specifc situations, students can evaluate the efectiveness of meditation practices as a stress management tool; however, a nonmedical intervention group of students is likely to be unafected by these infrequent events.
It should also be noted that despite the widespread adoption of the blind method, assessing perceived improvement in students' psychological distress and well-being is a complex issue because the assessments were conducted by students themselves.As such, they are subjective, even when considering the heterogeneity of the questionnaire tools used to validate such assessments.It should also be considered that in the psychological context, no measure can fully defne the complexity of behavior in the real world, and measures of abstract mental constructions can only provide an indirect assessment.Te psychological questionnaire instruments in the included studies involved self-reporting by students; therefore, the potential bias caused by selfreporting, for example, social desirability bias, could not be controlled for.However, given that the instruments used to measure quality of life in the analyzed studies were all psychometrically sound, this limitation is unlikely to be serious.Egger's test funnel plot ruled out the probability of publication bias.
Tis meta-analysis has some limitations.Owing to our research design, we only included RCTs that were published in English; therefore, there is a possibility that some important, high-quality fndings that were not published in English may not have been included.Moreover, the quality of the included RCTs was generally adequate; however, though there was no indication of publication bias, the low number of studies decreases the reliability of this result.Given the small sample size of the included RCTs, highquality, large-scale clinical studies are needed to provide further evidence in the future.Multicenter studies with large samples are required to explore standardized intervention protocols, MBSR practitioners' professional knowledge, the inconsistent design of MBSR protocols (frequency, intensity, content, and duration), the heterogeneity of control groups, and university students' physical and sociological characteristics.Tese factors may greatly afect the clinical signifcance of MBSR in terms of the average efect of the intervention on university students' overall quality of life.Tese clinical and methodological factors may, consequently, have afected the reliability of the conclusions drawn in extant research.
Te efects and infuences of mindfulness decompression psychological interventions on psychological outcomes, quality of life, emotional habits, and behavioral disorder symptoms among university students remain unclear.Intervention elements, such as the environment of mindfulness decompression psychological intervention in colleges and universities, university students' mindfulness communication and expression abilities, the level of language communication, and the standardized implementation guidelines for diferent intervention subtypes require further research.Future studies should aim to use larger samples, diferent forms of mindfulness, and long-term follow-up.Tey should also aim to obtain detailed information on sociodemographic variables and the intermediary and regulatory variables of mindfulness decompression psychological interventions.All these factors need to be explored further.

Figure 3 :
Figure 3: A forest plot of the efects of the group mindfulness-based stress reduction therapies on treatment-related side efects.Te width of the horizontal lines represents the 95% confdence intervals (CIs) of the individual studies, and the squares represent the proportional weight of each study.Te diamonds represent the pooled odds ratio and 95% CI.(a) Anxious, (b) depression, (c) perceived stress, (d) sleep quality, (e) mindfulness, (f ) self-kindness, (g) social function, (h) subjective well-being, and (i) physical health.

Figure 4 :
Figure 4: Forest plot of the efect sizes of subgroup analysis of mindfulness-based stress reduction therapies.Te width of the horizontal line represents the 95% CI of the individual studies, and the square proportional represents the weight of each study.Te diamond represents the pooled OR and 95% CI.(a) Subgroups for anxious, (b) subgroups for perceived stress, and (c) subgroups for subjective well-being.

Figure 5 :
Figure 5: Funnel plot displaying the probable publication bias in the overall estimated pooled efect size of MBSR on primary outcomes.(a) Anxiety, (b) depression, (c) mindfulness, (d) perceived stress, (e) self-kindness, and (f ) subjective well-being.

Table 1 :
Systematic review search strategy: research terms used to identify RCT of mindfulness-based stress reduction in those databases.

Table 1 :
Continued.undergraduate education and mindfulness or Mindfulness meditation or Kabat-Zinn programme or Kabat-Zinn protocol or Kabat-Zinn or mindfulness-based stress reduction or mind-body skill training or MBSR

Table 2 :
Characteristics of the included studies.

Table 3 :
Methodological quality of the included studies.

Table 4 :
Efect sizes of MBSR versus control interventions.

Table 6 :
3RADE quality of evidence assessment for the efect of mindfulness-based stress reduction on the symptom management of postoperative side efects among university students.Some RCTs did not mention using the blind method or randomized grouping.2Similarity of point estimates, extent of overlap of confdence intervals, and statistical criteria are poor.3