Mindfulness-based interventions for improving cognition,academic achievement,behavior,and socioemotional functioning of primary and secondary school students

1.1 THE PROBLEM, CONDITION OR ISSUE

Evidence suggests that students today are experiencing high levels of stress as well as other emotional and developmental challenges that may impede their ability to learn and succeed in school (APA, 2009; Merikangas et al., 2010; Pope, 2010). Approximately 13%-20% of children in the U.S. experience at least one mental disorder, and these rates have been on the rise since 2005 (Centers for Disease Control and Prevention, 2013). The increased prevalence of stress and anxiety, and at earlier ages than prior generations, has been at least partially attributed to school-related stress—particularly, high stakes testing, increased academic pressure, and the overscheduling of students in multiple extracurricular activities (APA, 2009; Gregor, 2005; Pope, 2010; Suldo et al., 2009). Indeed, students report school-related stress as being their greatest source of stress (APA, 2009) and teachers rate behaviors associated with anxiety as some of the most common problems of children and adolescence (Harrison, Vannest, Davis & Reynolds, 2012). The prevalence and levels of student stress and anxiety has become a concern for schools as emerging evidence suggests strong links between stress and anxiety with academic performance as well as with emotion regulation, behavioral functioning, and brain and cognitive development, which are also strongly linked to academic performance (Andersen, 2003; Andersen & Teicher, 2009; Sandler et al., 2000; Shonkoff et al., 2009; Suldo et al., 2009; Teicher et al., 2002; Wolchik et al., 2006).

Social-emotional development and competencies have also been linked to learning and academic achievement and increasingly viewed as a target for school-based interventions (Zins & Elias, 2006; Eisenberg, Spinrad, & Eggum, 2010; Durlak, Weissberg, Dymnicki, Taylor, & Schellinger, 2011). A growing body of evidence has found numerous social and emotional factors, including emotion regulation, effortful control, social and self-awareness, self-management, relationships skills and decision-making, to be directly and indirectly related to academic performance, school engagement, and externalizing and internalizing behaviors (Brackett & Rivers, 2014; Denham & Brown, 2010; National Center for Educational Statistics, 2002; Wang et al., 1997). Social-emotional competencies are positively related to academic success, greater impulse control, better concentration and attention in school, whereas a lack of social-emotional skills is linked to academic, social and behavioral problems (See Eisenberg et al., 2010 and Denham & Brown, 2010). For example, an inverse relationship between emotion regulation and effortful control has been found with externalizing behavior problems in pre-school age children through adolescence (Eiden et al., 2007, Eisenberg et al., 2004; Gardner et al., 2008). Conversely, students who exhibit greater ability to self-regulate are more likely to demonstrate better ability to concentrate and pay attention in school and exhibit better impulse control and fewer externalizing behaviors, leading to improved functioning and success in school (Eigsti et al, 2006; Eisenberg et al., 2010; McClelland et al., 2007; Mischel et al., 1989).

The increased prevalence of stress, anxiety, mental health problems and other social, emotional, and behavioral risk factors, along with the increase in knowledge of the impact of these factors on learning and achievement, has prompted schools and policy-makers to begin to more explicitly attend to students’ social and emotional functioning through both curricula and ancillary programs (Zins & Elias, 2006). Indeed, for students to succeed in school, it seems ever more apparent that schools need to provide strong social and emotional components and support students’ well-being in addition to providing strong academic curriculum and instruction (Zins, Weissberg, Wang, & Walberg, 2004).

As schools have struggled to find ways to support students’ overall well-being, one approach receiving growing interest is the use of mindfulness practices. Mindfulness, commonly defined as “paying attention in a particular way: on purpose, in the present moment, nonjudgmentally” (Kabat-Zinn, 1994, p. 4), has become mainstream and practiced by high profile stars and athletes as a means of improving health, well-being and athletic performance. Indeed, mindfulness was featured on 60 Minutes, free lessons in mindfulness are given as perks at companies like Google (Walton, 2014), and meditation is an integral part of the Seattle Seahawks training regimen (Roenigk, 2013). Google “mindfulness” and millions of news articles, video and audio files, images, books, practice guides and links to various centers for mindfulness will be listed in the results. From a simple Google search, it appears that mindfulness is a common topic in the public sphere.

While mindfulness seems to be a popular trend being adopted by individuals, it is also beginning to be considered in various areas of public policy, including education policy. Over the past decade, interest in mindfulness has been growing and mindfulness-based approaches to improving health and well-being, particularly with adults, has spread across fields, including psychology, healthcare, neuroscience, and business. This burgeoning interest in mindfulness is due, at least in part, to a significant and growing body of evidence pointing to positive effects of mindfulness training on cognitive processes. Evidence suggests that mindfulness practice improves performance on a variety of measures of self-regulation (Lo & Allen, 2008; Heeren, Van Broek, & Philippot, 2009) and emotion regulation (e.g., Speca et al., 2000; Fincune & Mercer, 2006), as well as enhancing cognitive functions such as attention, working memory and some executive functions (Chiesa, Calati, & Serretti, 2011), all of which are important to success in school. Indeed, Mindfulness interventions have been found to alter brain structure and function, including increased blood flow to and thickening of the cerebral cortex (Davidson, 2008) and increased gray matter concentration in areas of the brain involved with emotion regulation, learning and memory (Holzel et al., 2011). A meta-analysis of 21 neuroimaging studies found consistent differences between meditators and non-meditators in eight regions of the brain key to meta-awareness, body awareness, memory and self and emotion regulation (Fox et al., 2014).

Moreover, mindfulness has been found to be effective in the treatment of a myriad of health, social and psychological problems. Numerous studies and meta-analyses have investigated the use of mindfulness-based interventions (MBIs) in medicine, with mindfulness training and practice being found to help patients with chronic conditions manage pain (e.g., Cramer, Haller, Lauche, & Dobos, 2012; Veehof, Oskam, Schreurs, & Bohlmeijer, 2011), fibromyalgia symptoms (i.e., Lauche, Holger, Dobos, Langhorst, & Schmidt, 2013), and reduce stress in breast cancer patients (i.e., Zainal, Booth, & Huppert, 2013). Additionally, syntheses and meta-analyses have found positive effects of MBIs in treating individuals with mental health diagnoses, such as anxiety (deVibe et al., 2012; Vollestad, B. Nielsen, & H. Nielsen, 2012), psychiatric disorders (i.e., Chiesa, Calati, & Serretti, 2011), psychosis (Khoury, Lecomte, Gaudiano, & Paquin, 2013), personal development and quality of life (deVibe et al., 2012) as well as stress in healthy people (i.e., Cheisa & Serretti, 2009) including university students (Regehr, Glancy, & Pitts, 2013). Indeed, the use of mindfulness has greatly expanded into various fields to aid in the treatment of a vast array of conditions as well as to more generally enhance health and wellbeing.

While the vast majority of research on mindfulness has historically been focused on adults, the increase in promising research based on the diverse application of MBIs with adults and the growing popularity of mindfulness with the general public has naturally led to the extension of mindfulness to the application with children and youth (Zenner et al., 2014). It has been argued that children could benefit from mindfulness in ways similar to adults (Davis, 2012; Hooker & Fodor, 2008), and initial reviews suggest that MBIs are feasible with children and adolescents with adaptations (Burke, 2009; Zelazo & Lyons, 2012). Mindfulness-based interventions (MBIs) have been adapted from adult interventions or developed specifically for youth for a range of clinical conditions as well as more generally to enhance health and well-being, and applications for use in schools are also gaining attention.

The use of MBIs is on the rise in schools across the United States and United Kingdom as more and more schools have begun implementing various mindfulness-based programs and integrating mindfulness into the curricula (e.g., MindUP, The Inner Resilience Program, South Burlington Wellness and Resilience Program, Mindful Schools, Learning to Breathe, Mindfulness in Schools Project, Still Quiet Place, Stressed Teens, and Wellness Works in Schools). Moreover, efforts to promote mindfulness practices are being included in public policy initiatives. In the United Kingdom, for example, members of parliament have received training in mindfulness and have heard testimony of the evidence and benefits of mindfulness, including testimony from thousands of school children who have experienced mindfulness training in school. Also, an all-party parliamentary group was launched in the United Kingdom to conduct a nine-month inquiry into the potential role of mindfulness in areas of public policy, including education (Booth, 2014). The third session of the all-party parliamentary group focused on “mindfulness in health and education”, and members considered possible applications of mindfulness, with discussion of challenges for scaling up mindfulness programs to be included in teacher training as well as other potential policy actions (http://parliamentarywellbeinggroup.org.uk).

Although the use of MBIs appears to be on the rise in schools, and policy makers are calling for more mindfulness in education policy, it is unclear whether mindfulness-based approaches do indeed positively impact academic, emotional, and behavioral outcomes in students. While there is a growing body of studies of MBIs on a range of cognitive, social, and psychological outcomes including working memory, attention, academic skills, social skills, and emotional regulation (Meiklejohn et al., 2012), few studies have synthesized this literature using systematic and quantitative methods and few have focused specifically on school-based interventions. As schools develop practices and policies to try to more effectively and efficiently improve student outcomes, it is important that researchers, practitioners, policy makers, and other key stakeholders have access to evidence of effects of MBIs to make informed decisions rather than rely on anecdotal evidence and follow current popular trends. This information is critical as schools must make important academic, curricular and budgetary decisions. If a particular psychosocial intervention has large positive effects, then the use of academic time and limited school resources may be warranted to implement such a program during the school day; however, if the effects are minimalor adverse, then the use of academic time and limited school resources may not be worth those costs.

1.2 THE INTERVENTION AND HOW IT MIGHT WORK

Mindfulness was defined by Kabat-Zinn (1994) as “paying attention in a particularly way: on purpose, in the present moment, and non-judgmentally” (p. 4). Mindfulness is a type of practice derived from the Buddhist contemplative practices and traditions of Vipassana and Zen/Chan (Chiesa, Calati, & Serretti, 2011; Eberth & Sedlmeier, 2012), which is characterized by awareness of the current state of the mind and body without judgment, elaboration, or attachment (Burke, 2010; Eberth & Sedlmeier, 2012). Many scholars have embraced a two component model of mindfulness which includes self-regulation of attention and attending to the present moment. Self-regulation of attention refers to bringing awareness to a point of full attention to one's thoughts, feelings, and sensations. This includes maintaining sustained attention, keeping attention flexible, focusing on direct/current experience and inhibiting elaborate processing. The second component, orientation to the present moment, refers to the attitude or approach one takes in attending to the present moment and is exemplified by curiosity, openness, and acceptance (Bishop et al., 2004). Shapiro and colleagues (2006) conceptualized mindfulness as being comprised of three core components: intention, attention and attitude. The second and third components are similar to the two-component model described above. It's in the first component, intention, that their model differs. Intention involves the ability to regulate attention in a conscious and purposeful way. Shapiro and colleagues assert that one's intention for undertaking mindfulness practice (e.g., self-regulation, self-exploration, self-liberation) has been largely overlooked, but is important and may evolve over time.

While several models have been put forth to describe components of mindfulness and explain processes by which MBI's may work (e.g., Grabovac et al., 2011; Howell & Buro, 2011;Jankowski & Holas, 2013; Melbourne Academic Mindfulness Interest Group, 2006; Shapiro et al., 2006; Shapiro et al., 2011; Zelazo & Lyons, 2012), the specific mechanisms of mindfulness have not been fully explicated. Most models propose on one or more possible mechanisms, including cognitive, psychological and neurobiological mechanisms. We will focus on mechanisms that are most relevant to school-related outcomes of interest to this review (see Figure 1).

OPEN IN VIEWER

Figure 1

Logic model for MBIs with school students

Evidence suggests that mindfulness invokes cognitive processes and functions that are important to academic achievement, socioemotional functioning and behavior, namely attention, self-regulation, working memory, executive function, and metacognitive awareness (Grabovec et al., 2011; Melbourne-Based Mindfulness Interest Group, 2006; Zelazo et al., 2012; Shapiro et al., 2006). Some of these constructs are fairly broad, have overlapping components or are described or classified in the literature differently, thus making discussing the mechanisms involved in mindfulness interventions somewhat challenging. For example, self-regulation is conceptualized in terms of encompassing attention in some literature, but maintained as distinct constructs in others. Despite the variation across the literature in the ways in which cognitive processes are defined and measured, it is well recognized that cognitive processes are targeted and affected by MBI's and are important to academic achievement and socioemotional and behavioral outcomes.

As noted above, “paying attention” is a key component of mindfulness practice, requiring one to focus and direct attention in specific ways. Evidence suggests that mindfulness can enhance various aspects of attention or affect brain structure in areas related to attention (Carmody, 2009; Chiesa et al., 2011; Napoli et al., 2005). Given that a student's ability to sustain attention in class and on the right things is critical, and that performance and behavior are positively associated with attention (Hart, 2004; Rudasill, Gallagher, & White, 2010), MBI's could improve school achievement and behavior by helping students focus and sustain attention in school.

Self-regulation is another mechanism by which mindfulness may positively affect school-related outcomes. Self-regulation generally refers to monitoring and controlling our thoughts, actions and emotions (Zelazo & Lyons, 2012). It is often divided into cognitive self-regulation (including executive function, attention, planning) and emotional self-regulation (behavior and mental health; Duncan & Magnuson, 2009) and studied under the umbrella of executive function, which may also include working memory, cognitive flexibility, and inhibitory control (Zelazo & Lyons, 2012). The ability to monitor and control one's thoughts, behaviors and emotions plays an important role across all life domains, including school related outcomes. Self-regulation has been found to be related to, or a predictor for, a number of outcomes important to student success in school, such as externalizing and internalizing problems, classroom behaviors and disciplinary incidents, and math and reading (Berking & Wupperman, 2012; Ponitz et al., 2009; Quinn & Fromme, 2010; Richardson et al., 2012; Setken et al., 2010; Wyman et al., 2010). Evidence suggests that mindfulness positively effects self-regulation, as operationalized and measured in a variety of ways, and has been associated with changes in brain regions underlying self-regulation (Holzel et al., 2011). MBIs target self-regulation in that mindfulness practice requires one to attend to one's thoughts in the present moment and accept those thoughts without trying to change the thoughts or engage in action, promoting sustained attention and cognitive flexibility while also reducing emotional reactivity (Zelazo & Lyons, 2012). The emphasis on attending with acceptance and with a nonjudgmental attitude enables students to engage in more socially appropriate behavior and promote well-being by viewing situations through a different perspective and engaging in a type of detachment, which allows one to consider other potential responses and disrupt typical patterns of thinking and acting (Hart, 2004; Zelazo & Lyons, 2012). Thus, through cognitive and emotional self-regulation, MBIs may improve academic and behavioral outcomes, reduce mental health symptoms, and improve socioemotional well-being.

While mindfulness has been associated with a number of positive outcomes and may invoke a variety of potential mechanisms, mindfulness is a broad construct and interventions using mindfulness vary. This review will focus on MBIs with preschool, primary and secondary students in school settings. A number of MBI's being used in schools are being adapted from MBIs used with adults and others are being developed specifically for use with youth. For example, Mindfulness Based Stress Reduction (MBSR; Kabat-Zinn, 1979) and Mindfulness-Based Cognitive Therapy for Children (MBCT-C; Semple, Reid, & Miller, 2005), are MBIs that were originally developed for adults and have been adapted for youth. MBSR, a group intervention aimed at reducing stress, is composed of eight weekly 2.5-hour sessions with a daily 45-minute homework assignment (Grossman, Niemann, Schmidt, & Walach, 2004). Participants receive instruction in various aspects of mindfulness, including mindful awareness during meditation, yoga, and are taught to engage in continuous awareness of physical, mental, and emotional states without judgment or evaluation. Mindfulness based cognitive therapy (MBCT) was originally developed by Segal, Williams, and Teasdale (2002) as a treatment to reduce relapse of recurrent major depressive episodes in adults and was later adapted for use with children (MBCT-C; Semple, Reid & Miller, 2005; Semple, Lee, Rosa & L. Miller, 2010) to address anxiety. Researchers have adapted and implemented MBSR with children in clinical settings (Bootzin & Stevens, 2005), community settings (Saltzman & Goldin, 2008) and school settings (Bakosh, 2013; Bakosh, 2015; Sibinga, 2013; Sibinga, 2015). Both MBCT (for adults) and MBCT-C combine mindfulness-based practices such as attention on the breath and awareness of the present moment with cognitive interventions to achieve “affective self-regulation” (p. 222), but the children's version has been reduced from 12 weeks to 8 weeks in duration, there is less amount of time of each seated period and group size is smaller (Semple et al., 2010). Another distinction between the adult and child programs is that MBCT-C encourages parental involvement in the form of information sessions, brief mindfulness training exercises, and home practice of meditation with children. Since its development, several studies of MBCT-C in school settings have been conducted (i.e., Semple et al., 2005), as well as in other settings (e.g., Lee, Semple, Rosa, & L. Miller, 2008; Bogels, Hoogstad, van Dun, DeShutter, & Restifo, 2008).

Learning to BREATHE (L2B; Broderick & Metz, 2009) is an example of an MBI that was designed specifically for the classroom setting. The curriculum “tailors mindfulness-based approaches to the developmental needs of adolescents” (p. 38) by helping students be mindful of their present situation through lessons on body, thought, and emotion awareness, reducing self-judgment, and being mindful in everyday life (Broderick & Metz, 2009). L2B is a brief, six, twelve, or sixteen week curriculum conducted in a group setting that has been integrated into school curriculum in health class (Broderick & Metz, 2009) or choir class (Metz, Frank, Reibel, Cantrell, Sanders, & Broderick, 2013). Each lesson includes a short overview of the mindfulness principle being studied, group discussion, time to practice mindfulness by applying the principle, and home meditation practice assignments with supporting materials provided (Broderick and Metz, 2009; Metz et al., 2013).

In the descriptions of these approaches, one can discern that there are more similarities between MBI approaches than differences. For example, all of the approaches incorporate a training period of guided meditation techniques focusing on mindful attention and awareness of breath, body, or mind and followed by independent practice. The interventions differ in their intended purposes, such as treatment of anxiety and stress, managing aggressive behaviors, emotional regulation, and overall health promotion and how they are implemented in school settings. MBIs have been implemented in “core” content classes (reading and Language Arts, math, science, or social studies), in “elective periods” such as physical education classes (Napoli et al., 2008), choir classes (Metz et al., 2013), enrichment or intervention periods, or in time outside the regular school day (e.g., after-school tutoring or summer school). The type of setting is often determined by the purposes or outcomes measured, as well as the practical and systemic constraints and requirements in the school. For example, Broderick & Metz (2009) examined outcomes related to mental health by conducting the intervention in students’ health classes.

While many of the MBIs discussed to this point intervene directly with the youth, there are MBIs that also involve parents or teachers, either as a supplement to student training or as the primary target of the intervention. For example, Semple and colleagues (2010) conducted parent-training sessions in mindfulness, which provided an overview of the program their children would be receiving at school, as well as some opportunities for the parents to engage in mindfulness practice. Parents were also encouraged to participate in their child's home practice sessions; however, no data were collected or analyzed as a result of these parent-training sessions. It is yet unclear whether parent or teacher participation in the intervention provides any added benefit or enhances student outcomes. Other MBIs have been conducted with teachers or parents as the primary or only recipient of the intervention. In these interventions, the intent of providing teacher or parent training is to affect parent or teacher outcomes, with some hypothesizing indirect outcomes on students through changes in parent or teacher behavior from mindfulness practice. For example, Jennings and colleagues (2011) examined the effects of Cultivating Awareness and Resilience in Education (CARE), a mindfulness-based professional development program designed for teachers to reduce stress, improve teachers’ performance, and prevent “burnout.” Instruction in CARE provides teachers with training in a series of mindfulness activities, with periods of silent reflection and opportunities to extend the practices into daily classroom routines. Teachers reported high satisfaction with the CARE training, but there were no measures of student performance. Because MBIs that target teachers or parents as the primary recipient of the MBI focus on different outcomes (teacher and parent outcomes versus student outcomes, with perhaps some secondary student outcomes), we believe it is most appropriate to separate interventions targeting students from studies targeting teachers or parents as the primary recipient of the intervention. Therefore, we will focus this review on interventions in which students are the primary recipients of the MBI.

1.3 PRIOR REVIEWS

While several reviews have been conducted on mindfulness-based interventions with adults for a myriad of problems and outcomes, less attention has been given to reviewing the literature on outcomes of mindfulness-based approaches for children and youth, particularly outcomes relevant to education. To date, we have located nine reviews of mindfulness-based interventions that include studies with children or youth. One of the reviews focused on health-related effects of sitting-meditative practices (Black, Milam, & Sussman, 2009) and two reviews were not specifically focused on children or education, but did include some studies of mindfulness-based approaches with children and/or youth with intellectual disabilities (Chapman, 2013) and developmental disabilities (Hwang & Kearney, 2013). The remaining five reviews examined effects of MBIs with children and youth and are more relevant to the proposed review, thus will be discussed in more depth.

Meiklejohn and colleagues (2012), Greenberg and Harris (2012), and Thompson and Gauntlett-Gilbert (2006) published traditional narrative reviews describing mindfulness interventions with children and youth. Meikeljohn and colleagues focused on literature related to integrating mindfulness training in primary and secondary education, whereas Greenberg and Harris and Thompson and Guantlett-Gilbert reviewed mindfulness practices in clinical settings or prevention or health promotion contexts. All three reviews described a variety of mindfulness-based approaches and two summarized findings of intervention studies. These reviews concluded that mindfulness-based approaches are feasible and promising, but cautioned that additional and more rigorous research was needed. While these reviews provide an overview of MBIs with children and youth, the authors did not describe their search, selection, or coding procedures and did not quantitatively synthesize effects of the interventions, thus limiting the conclusions that can be drawn regarding the effects of MBIs with children and youth.

In addition to several narrative reviews, three reviews were identified that used systematic review methods (Burke, 2010; Zenner, Hernleben-Kurz, & Walach, 2014; Zoogman, Goldberg, Hoyt, & Miller, 2014), two of which also quantitatively synthesized effects using meta-analytic methods (Zenner et al., 2014; Zoogman et al., 2014). Burke (2010) conducted a systematic review of mindfulness-based approaches with children and adolescents. Burke identified 15 studies (6 used a between-group design) that met review criteria that included articles written in English and studies that used secular contemplative mindfulness mediation techniques. The author conducted a search for studies in 12 research databases and, although the author did not limit the review to published studies, a comprehensive search for grey literature was not conducted and dissertations or conference papers were not accessed. This review included studies of mindfulness with clinical and non-clinical samples, but not all included studies were relevant to education (e.g., outpatient gastroesophageal reflux, body weight) and only four were conducted in school settings. Eight of the studies included in the Burke review were also included in the Meiklejohn review. Burke concluded that the studies provided evidence of the feasibility and acceptability of mindfulness-based approaches for children and adolescents, but the research base is limited by a lack of rigorous efficacy studies, which was attributed, in part, to the early stage of research in this area.

Two meta-analyses of MBIs with children and youth have been published. Zoogman et al., (2014) reports the first published meta-analysis of mindfulness meditation with youth. The search was conducted in 2011 and was limited to peer-reviewed journal articles published in English. Twenty studies (13 RCTs, 1 QED, and 6 within group pre-post test studies) reporting effects of mindfulness interventions with clinical and non-clinical samples were included in the meta-analysis. The mean effect of the included interventions was 0.227 [CI 0.148, 0.305] and heterogeneity was not significant. Of the 12 moderators tested, only one moderator was significant—studies using clinical samples reported significantly larger effect sizes than studies using non-clinical samples. Additional analyses performed found significantly greater effects for psychological symptoms than measures of other outcomes. Zenner and colleagues (2014) conducted a systematic review and meta-analysis of MBis in schools with a focus on psychological outcomes (cognitive performance, emotional problems, stress and coping, and resilience). The authors conducted a comprehensive search in 2012 for published and unpublished reports yielding 24 studies (10 RCTs, 8 QEDs, 1 two-armed cohort study, and 5 non-controlled trials). The mean effect of the 19 studies using a comparison group design was g = 0.40 [0.21, 0.58]. The authors found significant effects on cognitive performance, resilience, and stress measures and non-significant effects on emotional problems. The authors found significant heterogeneity between studies. The included studies were often underpowered and small, and a wide variety of programs were evaluated, with many researchers implementing their own programs. The authors concluded that mindfulness-based approaches in schools are promising and the available evidence justifies allocating resources to mindfulness intervention implementation and evaluation. They recommended that larger studies employing more robust and well-validated measures be used in future research.

1.4 WHY IT IS IMPORTANT TO DO THE REVIEW

The aforementioned reviews contribute to our understanding of mindfulness-based approaches with children and youth; however prior reviews are limited in several ways. First, most prior reviews used non-systematic search methods and narrative synthesis methods, are not directly relevant to education settings, or were limited by including only published studies, thus limiting their applicability to informing practice and policy in education. This systematic review expands and improves upon prior work in several ways. First, this review focused on a range of outcomes relevant to educational settings and included academic performance outcomes. As academic performance outcomes have not been included in prior reviews, the present review provides timely information that can be used in school policy and practice decisions. Second, this review employeda systematic and transparent process for searching, retrieving, and coding studies, and in cluded searches for unpublished studies. Using a systematic method to conduct the review of outcome research limits bias and reduces chance effects, leading to more reliable results (Cooper, 1998). Further, explicitly and transparently describing the review process allows for others to replicate and expand the review to include new studies or criteria.

In short, this review contributes to the literature by including the most recent research on MBIs in school settings, including outcomes that have not been included in prior reviews of school-based MBIs, and employing stringent criteria for search, selection, coding, and analysis as specified in the Campbell Collaboration policies and guidelines. Thus, this review provides the most up-to-date and rigorous review of MBIs to inform educational policy and practice and identify gaps in the current evidence base to guide future research.

3.1 CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW

3.2 SEARCH METHODS FOR IDENTIFICATION OF STUDIES

3.3 DATA COLLECTION AND ANALYSIS

3.4 DEVIATIONS FROM THE PROTOCOL

We experienced circumstances that required us to deviate from the protocol at times. During the literature search, the CINHAL and FRANCIS databases were undergoing technical difficulties and we were not able to access those databases, thus we did not search those databases as planned. We found six studies that measured physiological outcomes. While six studies measured physiological outcomes, not all studies measured the same, or enough of the same conceptually similar outcomes to warrant meta-analysis. Thus, we did not quantitatively synthesize effects of physiological outcomes, but rather provided a descriptive analysis of these studies. Also of note is that we did not originally plan to document adverse outcomes, but decided post-hoc to review studies for reporting of adverse outcomes.

4.1 RESULTS OF SEARCH

Electronic searches of bibliographic databases and searches of other sources identified a total of 1353 citations. Titles and abstracts were screened for relevance and 1260 were excluded as duplicates or deemed inappropriate. The full text of the remaining 93 potential studies was reviewed and screened for eligibility by two independent coders. Sixty-onestudies passed full-text screening and were included in the review. See Figure 4.1 for the flow chart of the study selection process.

OPEN IN VIEWER

Figure 4.1

Flow chart of study selection process

4.2 DESCRIPTION OF INCLUDED RCT & QED STUDIES

Of the 44 RCT and QED studies, seven were unpublished reports, with the remaining being published studies in peer-reviewed journals. Most of the studies were conducted in North America (74%), with others conducted in Asia (5%), Europe (16%) and Canada (5%). All studies were written in English, with the exception of Justo et al. (2011) written in Spanish. Sample sizes ranged from 23 to 557, with a mean sample size of 141. The studies measured one or more of the outcomes of interest: 10 studies measured cognitive outcomes, 5 measured academic outcomes, 13 measured behavioral outcomes, 28 measured socioemotional outcomes and 6 measured physiological outcomes. No studies reported adverse outcomes. See Table 4.1 for a summary of characteristics across the included 44 studies as well as the subgroup of the 35 studies included in at least one meta-analysis.

4.3 RISK OF BIAS IN INCLUDED RCT & QED STUDIES

Overall, there was a moderate to high risk of bias across the 35 studies included in the meta-analyses, with variation in high risk areas across studies. (See Figure 4.3 for a summary of risk across studies, Appendix 8.7 for a Table reporting each domain of risk for each study and Appendix 8.xx for a for Risk of bias within studies.

OPEN IN VIEWER

Figure 4.3

Risk of bias across studies

4.4 SYNTHESIS OF RESULTS

4.4.1 Mean effects on cognitive outcomes

Twenty effect sizes from 10 studies were synthesized to examine effects on cognitive outcomes. Results indicate that the overall mean effect (Hedges’ g) at post-test on cognitive measures was 0.25 (95% CI [0.06, 0.43], p = .01). Heterogeneity analysis indicated a low amount of heterogeneity (I ² = 25%) that was not statistically significant (Q = 12.10, p = .21). The mean effect size and confidence intervals for each study are shown in the forest plot in Figure 4.4 below. See Appendix 8.8 for a full list of all measures of cognitive outcomes included in this meta-analysis by study.

OPEN IN VIEWER

Figure 4.4

Forest plot of mean effects on cognitiveoutcomes

4.4.2 Mean effects on academic outcomes

Fifteen effect sizes from five studies were synthesized to examine effects on academic outcomes. Results indicate that the overall mean effect (Hedges’ g) at post-test on academic outcomes was 0.27 (95% CI [-0.04, 0.57], p = .08.). Heterogeneity was not significant (I² = 0%; Tau² = .00Q = 0.52, p= .97). The mean effect size and confidence intervals for each study are shown in the forest plot in Figure 4.5 below. See Appendix 8.9 for a full list of all measures included in this meta-analysis by study.

OPEN IN VIEWER

Figure 4.5

Forest plot of mean effects on adademic outcomes

4.4.3 Mean effects on behavioraloutcomes

Twenty-eight effect sizes from 13 studies were synthesized to examine effects on behavioral outcomes. Results indicate that the overall mean effect (Hedges’ g) at post-test on behavioral outcomes was 0.14 (95% CI [-0.02, 0.30], p = .08). It is important to note that there was a moderate amount of heterogeneity (I ² = 48%; T² = .034; Q = 22.96, p = .03). The mean effect size and confidence intervals for each study are shown in the forest plot in Figure 4.6 below. See Appendix 8.10 for a full list of all measures included in this meta-analysis by study.

OPEN IN VIEWER

Figure 4.6

Forest plot of mean effects on behavioral outcomes

4.4.3.1 Moderator analysis for behavioral outcomes

We conducted moderator analyses to examine whether study or intervention characteristics could explain the variation observed across studies. None of the moderators examined were statistically significant: study type (Q _b = 3.51; p = .06), provider (Q _b = 0.71; p = .40), homework (Q _b = 0.28; p = .60), manualized program (Q _b = 7.27; p = .06), number of weeks(Q = .003; p = .97).

4.4.4 Mean effects on socioemotional outcomes

One hundred sixty-eight effect sizes from 28 studies were synthesized to examine effects on socioemotional outcomes. Results indicate that the overall mean effect (Hedges’ g) at post-test on socioemotional outcomes was 0.22 (95% CI [0.14, 0.30], p < .001). There was a small amount of heterogeneity (I ² = 14%; Q = 31.20, p = .263; Tau² = .01). The mean effect size and confidence intervals for each study are shown in the forest plot in Figure 4.7 below. See Appendix 8.11 for a full list of all measures included in this meta-analysis by study.

OPEN IN VIEWER

Figure 4.7

Forest plot of mean effects on socioemotional outcomes

4.5 PUBLICATION BIAS

There was a sufficient number of studies to examine publication bias for cognitive, behavioral and socioemotional outcomes using funnel plots (see Figure 8.12 in Appendix) and for socioemotional outcomes using Egger's linear regression approach (a minimum of 17 studies is recommended; Card, 2012). In examining the funnel plot for behavioral outcomes, the funnel plot appears relatively symmetrical, but the funnel plot for cognitive and socioemotional outcomes appears to be somewhat asymmeterical, with a larger number of studies clustering on the right side of the funnel. Results of Egger's regression for socioemotional outcomes was not significant (t = 1.76, p = .09), indicating an absence of publication bias in the studies contributing effect sizes for socioemotional outcomes. The funnel plot for cognitive outcomes, however, is less symmetrical, and few small sample studies with small effects were observed, indicating the possibility of publication bias.

5.1 SUMMARY OF MAIN RESULTS

The present review identified a total of 61 studies that met review criteria, including 44 randomized or quasi-experimental studies and an additional 17 studies that used a single-group pre-posttest design or single subject study design to examine effects of a school-based mindfulness intervention on a cognitive, academic, behavioral, socioemotional or physiological outcome. It is interesting to note that we observed an increase in the number of MBI studies over time, as a higher proportion of the included studies were published more recently. Of the included studies, 35 provided adequate effect size data to be included in a meta-analysis for at least one of the outcomes of interest for this review. Results indicate mixed results of school-based mindfulness interventions across the outcomes of interest in this review, with small positive effects observed on cognitive and socioemotional outcomes and positive, yet non-significant effects on academic and behavioral outcomes. The lack of heterogeneity for all outcomes with the exception of the behavioral outcomes indicate that the interventions in this review, although quite diverse in their characteristics, produced similar results across studies on cognitive, socioemotional and academic outcomes. These findings provide some support for the use of school-based mindfulness interventions for some outcomes, but do not provide overwhelming support of mindfulness interventions as being the panacea as some have advocated. Given the quality and high risk of bias across studies in several areas, caution must be used in the interpretation of the study results.

First, the results of this review largely correspond to what we would expect given the mechanisms by which mindfulness interventions are hypothesized to work. The proximal processes targeted by mindfulness interventions are cognitive processes, which are then hypothesized to impact more distal outcomes—academic, behavioral, and socioemotional outcomes. Our results provide support for favorable impacts of mindfulness interventions on those processes that are likely more directly targeted by mindfulness interventions, namely cognitive outcomes. Socioemotional outcomes may be a more proximal target as well as many of the measures were linked to emotional regulation processes that are invoked in mindfulness training. There is no direct support, at least not at posttest, to indicate that more distal outcomes, such as behavior and academic achievement, which are hypothesized to be impacted through improved cognitive and socioemotional outcomes, are affected by MBIs. It could also be that the effects found for cognitive and socioemotional outcomes may be due to the type of self-report measures typically used to measure these types of outcomes versus the administrative measures used to measure academic outcomes and observational measures to measure behavioral outcomes.

The mixed effects found in this review could be due to several possible explanations. First, as alluded to above, mindfulness interventions are most directly targeting cognitive and psychological/socioemotional processes. Thus, we expected that we would be more likely to find positive effects on those outcomes than behavioral or academic outcomes, which are arguably more distal outcomes. Mindfulness interventions may not be powerful enough to affect cognitive and socioemotional process sufficiently to mediate academic or behavioral outcomes as hypothesized by proponents of MBIs. Alternatively, since the vast majority of participants were not clinical or special needs populations, and were likely functioning within normal ranges across these measures (and thus have less opportunity to improve greatly), there may have been less opportunity for substantial improvement in the populations being studied, and thus small effects observed. Using mindfulness based interventions as a universal intervention with those already in normal ranges on cognitive, socioemotional and behavioral measures may be unnecessary, or perhaps measures need to be more sensitive to smaller changes to find effects when testing MBIs as a universal prevention strategy. It could also be that MBIs may have greater impact with students who are experiencing clinical, or high levels of, distress, anxiety or stress and could then have a greater impact on behavioral and academic outcomes. These issues require further exploration- examining differential impacts of MBIs with clinical versus non-clinical populations could provide some needed nuance to the MBI effectiveness literature.

The MBIs in this review were also shorter-term interventions. It is possible that MBIs may have a greater impact with greater dosage over longer durations. A number of authors and proponents of MBIs often cite the short duration as a limitation in observing effects of mindfulness on various outcomes (Carmody, & Baer, 2008; Carson, Carson, Gil, & Baucom, 2004; Chiesa, Calati, & Serretti, 2011; Jha, Stanley, Kiyonaga, Wong, & Gelfand, 2010), and some studies indicate that a longer duration would have greater effects (Mathew, Whitford, Kenny, & Denson, 2010; Miller, Fletcher, & Kabat-Zinn, 1995). Also, we examined effects of interventions at posttest, thus we are unsure what the longer-term effects of MBIs on proximal and distal outcomes. Academic outcomes are often more difficult to change immediately, and given that the studies in this review measured grades, it may take a longer measurement period to see meaningful change in grades, as well as the other outcomes of interest.

5.2 QUALITY OF THE EVIDENCE

The quality of the evidence varied, with some important risks of bias present across a large proportion of studies which threatens the internal validity of the included studies and is cause for caution in interpreting the results of this review. Overall, a large proportion of included studies presented with a high risk of bias related to allocation concealment and performance bias. In most studies, reporting bias was rated as unclear risk of bias, which is problematic as reporting bias is a potential threat and we could not adequately assess it in this body of literature. Publication bias may also be present in this literature, as some funnel plots were asymmetrical, thus indicating potential for publication bias on at least some of the outcomes. A large proportion of the studies included in this review were conducted by researchers who were likely invested in the programs (involved in development or implementation) and had tacit knowledge of the interventions, and participants and personnel were not blinded in the majority of the studies- thus we are concerned that this body of evidence is biased in favor of the MBIs due to allegiance and experimenter expectancy effects. In examining the results of the meta-analyses, the confidence intervals were fairly wide, with the exception of socioemotional outcomes, which were much narrower. This is reasonable in that we had a much larger number of studies and low heterogeneity across studies included in the meta-analysis for socioemotional outcomes. Thus, we can be more confident in the estimate of the average effect for socioemotional outcomes and less so in the average effect observed for cognitive, academic and behavioral outcomes. Also, a number of studies were confounded and, while the differences in mean effects were not significantly different for those studies that had a confound and those that did not, the magnitude of effects were larger in those that had a confound, and thus could be upwardly biasing the mean effect. Overall, there is room for improvement in the current evidence of effects of school-based mindfulness interventions.

5.3 LIMITATIONS AND POTENTIAL BIASES IN THE REVIEW PROCESS

We made every attempt to search for published studies; however, the majority of the studies included in this review were published journal articles, with approximately 20% being unpublished dissertations. Three of the databases were reviewed by only one of the authors, thus there may be a greater chance of errors in identifying potential studies from these three databases. The review authors did not use a formal method to assess the quality of the body of evidence; the authors did however assess risk of bias and reported on study characteristics that are indicators of study quality. There is some indication of publication bias present, which could be upwardly biasing the mean effect for all or some outcomes examined in this review.

5.4 AGREEMENTS AND DISAGREEMENTS WITH OTHER STUDIES OR REVIEWS

The findings of the present review largely correspond with other systematic reviews and meta-analyses of MBIs with children and youth. Narrative reviews, including those by Meiklejohn and colleagues (2012), Greenberg and Harris (2012), and Thompson and Gauntlett-Gilbert (2006) concluded that mindfulness-based approaches were feasible and promising, but cautioned that additional and more rigorous research was needed. Findings from a systematic review of 15 studies (6 between-group designs) of mindfulness-based approaches with children and adolescents (Burke, 2010) concluded that the studies provided evidence of the feasibility and acceptability of mindfulness-based approaches for children and adolescents, but the research base was limited by a lack of rigorous efficacy studies. Finally, two meta-analyses of MBIs with children and youth found positive and significant effects of MBIs on primarily psychological outcomes. Zoogman et al., (2014) reported a synthesis of studies examining mindfulness meditation with youth across outcomes, including psychological and non-psychological symptoms (specific outcomes are not reported). The search was conducted in 2011 and was limited to peer-reviewed journal articles published in English. Twenty studies (13 RCTs, 1 QED, and 6 within group pre-post test studies) were included in the review, yielding an overall mean effect of 0.227 [CI 0.148, 0.305], with lager mean effects found across studies using clinical samples compared to studies using non-clinical samples. Zenner and colleagues (2014) conducted a systematic review and meta-analysis of mindfulness-based interventions in schools with a focus on psychological outcomes. The authors conducted a search in 2012 for published and unpublished reports yielding 24 studies (10 RCTs, 8 QEDs, 1 two-armed cohort study, and 5 non-controlled trials). The mean effect across all outcomes of the 16 studies using a comparison group design was g = 0.40 [0.21, 0.58], with significant heterogeneity between studies. In the current meta-analysis of socioemotional outcomes (the outcome category that most closely aligns with the Zoogman et al. and Zenner et al. reviews), the mean effect of 0.21 is similar to the mean effect of 0.227 estimated by Zoogman et al. and smaller than the mean effect estimated by Zenner et al. The differences in mean effects between the present review and Zoogman et al. could be due to the inclusion of different outcomes, studies and effect size estimation procedures. The present review provides the first synthesis of effects specifically on cognitive, academic and behavioral outcomes in addition to the socioemotional outcomes reported in prior reviews.

6.1 IMPLICATIONS FOR PRACTICE AND POLICY

The number and types of MBIs being implemented in schools is expanding significantly, and intervention research is beginning to shed more light onto the effects and mechanisms of mindfulness interventions on a range of outcomes. Up to this point, much of the arguments and enthusiasm for the broad implementation of mindfulness-based approaches with children, as well as those in schools, have been predicated on generalizing the positive evidence from mindfulness research with adults and from expert opinion, or the use of cherry-picking studies in favor of MBIs to promote mindfulness interventions with children. This review adds to the body of evidence examining MBIs for children, and for the use of MBIs in school settings specifically. While the results of this review found positive effects favoring mindfulness interventions on cognitive and socioemotional outcomes, we urge caution in the use of these findings to support further implementation of MBIs in schools.

Schools often justify the implementation of socioemotional programs, including mindfulness-based training, on the premise that those programs will, in turn, promote positive behavior and improve academic achievement. The evidence to support MBIs to improve behavioral and academic outcomes, at least in the short-term, is not yet supported by the evidence. There is also seemingly widespread belief that MBIs, given the positive effects with adults, have great potential for direct and indirect benefits for students. Moreover, those who argue for an expansion of MBIs with children do not adequately, if at all, consider the costs or potential negative effects. Although rarely discussed and more rarely studied, adverse effects of mindfulness and meditation are gaining more attention, as Willoughby Britton, a mindfulness researcher at Brown, has begun to map and analyze accounts of harmful effects of contemplative practices, which include mindfulness and meditation (Rocha, 2014; Britton & Lindahl, 2015), through interviews with meditation teachers and practitioners from across a range of contemplative practice traditions. Some of her preliminary findings indicate that meditation can result in difficult or challenging experiences and cause or worsen symptoms. None of the studies included in this review measured potentially adverse outcomes, and if they didn't find positive effects, authors were more likely to provide justifications for why their intervention did not work rather than to consider that their intervention was not effective. There were exceptions to this, however. For example, Tharaldsen (2002) found that participants in their study experienced deterioration in life satisfaction and no improvement in psychological symptoms. They considered the possibility that their results “may be a result of an increased focus on troublesome emotions due to awareness training and a maladaptive use of distraction skills that lead to avoidance” and that “certain aspects of mindfulness can be more confusing than beneficial to adolescents” (Tharaldsen, 2012, p. 120). Indeed, children and adolescents may not benefit from mindfulness-based interventions similarly to adults, and there may be some adverse effects, because children and adolescents may not be developmentally ready for the complex cognitive tasks, focus and level of awareness that mindfulness-based interventions require (Melbourne Academic Mindfulness Interest Group, 2006; Shapiro, 1992).

There are also direct and indirect costs in implementing these interventions, and the cost-benefit of mindfulness-based intervention is largely ignored. The direct costs of implementing mindfulness-based interventions are those that are obvious to the implementation of any intervention in schools, namely the cost of materials and personnel needed to implement the intervention. The included studies did not provide sufficient information to calculate the total cost of the interventions that schools would be responsible for if they were to adopt these interventions. Indirect costs, but nonetheless important, are opportunity costs, specifically the cost of lost instructional time or not implementing something else that could be more effective (Melbourne Academic Mindfulness Interest Group, 2006). Some of these interventions were very short in duration, in that they only took up a few minutes of the school day on a daily basis and thus resulted in little lost instructional time. However, other interventions used more class time, or even an entire class period. It is unclear if the small effects gained from these interventions on cognitive and socioemotional outcomes are worth the lost instructional time. If the primary focus of schools is to enhance academic outcomes, then using instructional time to provide a universal MBImay not be a good use of time, considering that we found a lack of evidence for significant effects on academic outcomes. However, there remains yet much we do not know about the effects of MBIs, specifically whether students near or in the clinical range of anxiety or other emotional disorders may benefit more than students in the general population of the school. Prior reviews found some evidence for greater effects with children and adolescents from clinical populations (Zoogman et al., 2014), and thus there may be some students for which MBIs may be worth the cost and time.

Overall, the evidence from this review urges caution in the enthusiasm for, and widespread adoption of, MBIs for children and youth—specifically for use in schools. While the evidence points to positive effects on socioemotional and cognitive outcomes, there is a lack of evidence of effects on academic and behavioral outcomes. Moreover, we know little about the costs and adverse effects of school-based mindfulness interventions. The costs of implementing these programs may not be justified, and there are some indications that MBIs may have some adverse effects on children and youth that have not received adequate attention. If schools do want to implement MBIs, we urge schools to evaluate the practice in a rigorous way and monitor outcomes and costs.

6.2 IMPLICATIONS FOR RESEARCH

The number of studies examining effects of MBIs have expanded considerably, particularly over just the past few years. Clearly, there is much interest in examining the effects of school-based mindfulness interventions. However, a large proportion of studies in this review were conducted by authors who clearly had some involvement in the development, adaptation, or delivery of the intervention and thus were not independent evaluators. Moreover, several of the studies were funded by bodies that had an interest in the success of the MBIs being evaluated. Overall, authors engaged in the evaluation of school-based mindfulness interventions appear to be largely biased in favor of mindfulness interventions. This is problematic in that studies in which authors have some allegiance to the intervention or are otherwise involved in the development or implementation of the intervention are more likely to find positive effects than studies that are not conducted by authors with a vested interest in the outcomes of the interventions. The large proportion of studies in which authors had some role in the development and delivery of the interventions under investigation in this review may have biased the mean effect in favor of mindfulness interventions and overestimated the effects of these interventions. Moreover, the tacit knowledge that researchers who develop or implement the interventions they are testing may positively skew the outcomes in such a way that would not be replicable if someone with less knowledge or investment were implementing the intervention. It is recommended that future evaluations of MBIs be conducted by an independent third party investigator, and when possible, that personnel and assessors be blinded to group assignment.

Also, a significant number of studies in this review had major and troublesome confounds that clearly limits the extent to which we can draw causal inferences from this body of research. For each outcome examined in this review, all studies with confounds were biased in favor of the treatment group, thus resulting in an upward bias of the mean effect across studies. Future studies should avoid confounds in their study designs.

Other important areas in which to further develop school-based mindfulness intervention research is to move beyond mean effects of interventions and begin to explicitly examine the mechanisms of change (e.g., what are the pathways and mediators), which components of mindfulness interventions are effective and/or necessary (e.g., is home practice necessary and how much? Does yoga/movement enhance mindfulness practice), what works for whom and under what circumstances, and examine adverse effects of these interventions.