BRIEF RESEARCH REPORT published: 16 December 2021 doi: 10.3389/fpsyg.2021.717736 Testing the Efficacy of ‘Unlearning’, a Mindfulness and Compassion-Based Programme for Cultivating Nonviolence in Teenagers: A Randomised Controlled Trial Irene Delgado-Suárez 1†, Yolanda López-del-Hoyo 1,2,3†, Javier García-Campayo 1,3, Adrián Pérez-Aranda 1,4*, Marta Modrego-Alarcón 1,2,3, María Beltrán-Ruiz 1,3, Santiago Gascón 1 and Jesús Montero-Marín 5 1 Institute of Health Research of Aragon (IIS Aragón), Miguel Servet University Hospital, Zaragoza, Spain, 2 Department of Psychology and Sociology, Faculty of Social and Human Sciences, University of Zaragoza, Zaragoza, Spain, 3 Primary Care Edited by: Prevention and Health Promotion Research Network (RedIAPP), Zaragoza, Spain, 4 Department of Basic, Developmental and Evely Boruchovitch, Educational Psychology, Autonomous University of Barcelona, Barcelona, Spain, 5 Department of Psychiatry, Warneford State University of Campinas, Brazil Hospital, University of Oxford, Oxford, United Kingdom Reviewed by: Taylor Wayne Acee, Texas State University, United States Background: Most programmes developed to reduce aggressive attitudes among Julia Hein, teenagers are based on cultivating nonviolence, a construct that has been related to Universität Mannheim, Germany compassion and, more indirectly, mindfulness. This study aims at testing the efficacy of *Correspondence: Adrián Pérez-Aranda ‘Unlearning’, a mindfulness and compassion-based programme, for reducing aggressive aparanda@iisaragon.es attitudes in adolescents. These authors have contributed Method: A sample of 164 students from three high schools in Zaragoza (Spain) participated † equally to this work and share first authorship in the study. They were randomly assigned to (1) ‘Unlearning’, or (2) relaxation programme. Three assessment points were established: baseline, post-treatment and a 4-month Specialty section: follow-up. The outcome variables were the subscales of the ‘Attitudes Toward Social This article was submitted to Educational Psychology, Aggression Scale’. Mindfulness and compassion were assessed as secondary outcomes. a section of the journal Results: ‘Unlearning’ did not produce changes in the primary outcomes, but significant Frontiers in Psychology effects were observed post-treatment in self-compassion; and in the follow-up, in self- Received: 31 May 2021 Accepted: 22 November 2021 compassion and mindfulness. The control group did not experience any change post- Published: 16 December 2021 treatment, but a significant effect in mindfulness was observed in the follow-up. The Citation: intergroup analyses indicated that ‘Unlearning’ improved self-compassion, both post- Delgado-Suárez I, López-del-Hoyo Y, treatment (t = −2.48, p = 0.014) and after 4-months (t = −2.03, p = 0.044), although these García-Campayo J, Pérez-Aranda A, Modrego-Alarcón M, Beltrán-Ruiz M, results were not statistically significant after correcting for multiple comparisons. Gascón S and Conclusion: ‘Unlearning’ did not produce significant reductions in aggressive attitudes Montero-Marín J (2021) Testing the Efficacy of ‘Unlearning’, a compared to the control group. The low baseline levels may have hindered the efficacy of Mindfulness and Compassion-Based the interventions. ‘Unlearning’ showed potential to improve self-compassion, which is related Programme for Cultivating Nonviolence in Teenagers: A to nonviolence, and this may have positive implications for the adolescents. Future interventions Randomised Controlled Trial. should include teachers and families to enhance the effectiveness of the programmes. Front. Psychol. 12:717736. doi: 10.3389/fpsyg.2021.717736 Keywords: mindfulness, compassion, nonviolence, randomised controlled trial, teenagers Frontiers in Psychology | www.frontiersin.org 1 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers INTRODUCTION peace (Nagler, 2004). In the adult population, some studies have found promising evidence: the Freedom project, focused Teenagers constitute a population in high risk of experiencing on training prisoners in nonviolent communication, observed different types of violence. Bullying represents the most common significant effects of a mindfulness and compassion-based expression of violence among adolescents (Modecki et al., 2014; intervention in different outcomes, including anger (Suarez Smith, 2016). Despite data regarding its prevalence has shown et al., 2014). Wang (2018) also used mindfulness along with variability, high rates of victimisation have generally been other techniques to enhance nonviolence to the self in educators. reported; in Spain, 9.3% of the students of secondary centres In the case of teenagers, while some studies have not found have experienced bullying or cyberbullying (Observatorio de significant effects of mindfulness and compassion-based la Convivencia Escolar, 2016). Thus, there is a wide consensus interventions on violence-related constructs (Huppert and regarding the need of implementing policies addressed at Johnson, 2010; Schonert-Reichl and Lawlor, 2010; Tharaldsen, reducing aggressive attitudes among teenagers. 2012; Wongtongkam et al., 2015; Rawlett et al., 2019), some For that purpose, different programmes have been designed, others have reported promising evidence of the effect of such and most of them share some key elements, such as cultivating programmes on empathic and pro-environmental attitudes (Jalón nonviolence. Nonviolence can be defined by a series of et al., 2020) and on constructs such as hostility, lack of social interconnected values and principles: not killing would be the compromise, aggresivity and impuslivity (Nelson-Gray et al., very first, and subsequently, not producing harm or suffering 2006; Franco et al., 2016; Salmoirago-Blotcher et al., 2019; to oneself or other sentient beings (López-Martínez, 2004; Loy, Georgiou et al., 2020). However, these studies have been 2018). Many authors have underlined that, contrary to a general conducted on specific samples which do not represent the belief that considers nonviolence as a passive act, it involves general population of teenagers, and other limitations, such a strong positive exercise of loving other beings (Nagler, 2014; as the lack of an active control condition or a follow-up Garcia-Campayo, 2020), for which it has been related to assessment, imply that these results should be considered compassion (Wang, 2018), defined as an orientation to preliminary and that further research is needed. be sensitive towards suffering – both own and others’ – and This study aimed at analysing the efficacy of a mindfulness a commitment to relieve it by recognising its universality and and compassion-based programme, specifically designed for the ability to meet that pain with equanimity (Feldman and this project, named ‘Unlearning’. The intervention was addressed Kuyken, 2011; Macbeth and Gumley, 2012). at cultivating nonviolence through the practice of mindfulness Among the different approaches that have been conducted and self-compassion in teenagers who were studying secondary for promoting nonviolence and other related concepts, some education. ‘Unlearning’ was compared to an active control programmes have presented very promising results. For instance, condition, equivalent in terms of duration, consisting of a the ‘Olweus Bullying Prevention Program’ focused on aspects, programme addressed at teaching relaxation techniques and such as discipline, authority, limits and consequences, rewarding time management. The hypothesis of the researchers was that pro-social attitudes (Olweus and Limber, 2010), and it achieved ‘Unlearning’, which specifically addressed self-compassion significant changes in the ‘school culture’ regarding bullying attitudes and mindfulness, would significantly decrease aggressive (Olweus et al., 2020). On the other hand, the ‘KiVa’ programme attitudes among teenagers compared to the control condition, was addressed at teaching the teachers effective strategies for and these effects were expected to be maintained in the 4-month managing harassment situations and providing teenagers follow-up assessment. emotional education. This programme also produced significant decreases in self-reported rates of bullying and victimisation (Green et al., 2020). Another example would be the ‘Friendly MATERIALS AND METHODS Schools’ programme, based on promoting assertiveness and emotional regulation, among other abilities; a significant decrease Participants in reported bullying perpetration was observed after the Students from three secondary education centres in Zaragoza programme (Cross et al., 2019). Despite the variability that (Spain) participated in the present study. Once the informed the different programmes present, a meta-analysis indicated consent had been signed by both the student and their legal that these interventions produce significant reductions of around guardian, each participant was randomised to one of the 20% in bullying rates (Ttofi and Farrington, 2011). following study arms: (1) ‘Unlearning’; or (2) active control As abovementioned, nonviolence has been sometimes group (i.e. relaxation programme). The exclusion criteria for identified with the concept of compassion, and some studies participating in the study were not being able to attend to have analysed the role of self-compassion and other related the sessions due to schedule incompatibilities and/or changing constructs, such as mindfulness, on aggressive attitudes and of school during the following year. The sample size was victimisation (Dávila Gómez et al., 2020). Mindfulness is defined calculated assuming a large effect of ‘Unlearning’ vs. the as a present-focused, non-judgmental awareness whose practice relaxation programme in the primary outcomes, an equal 1:1 is associated with a wide range of positive mental health-related allocation rate and d = 0.80 when comparing the two study outcomes, also in children and teenagers (Zoogman et al., arms. It was estimated at 146 patients (73 per group); assuming 2015; Carsley et al., 2018). In the case of nonviolence, mindfulness an attrition rate of 10% at follow-up, the total sample size has been considered relevant for its capacity to promote inner required was established at 162 patients (81 per group). Frontiers in Psychology | www.frontiersin.org 2 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers Procedure to identifying the student’s needs through the practice of The present study was conducted during two academic courses: mindfulness and compassion, with the purpose of overcoming 2018–19 and 2019–20. This project was announced in the 2nd common limitations regarding teenager’s lack of interest or Congress of Mindfulness in Education (2017) and the 5th compromise towards mindfulness (McKeering and Hwang, 2019). International Mindfulness Congress (2018), which were held in Zaragoza, and in different mindfulness-based courses. Teachers Relaxation Programme who showed interest in the project were contacted for an The active control group presented an equivalent format to in-depth explanation of the aims and procedures, which were ‘Unlearning’ (i.e. 8 sessions of 45–50 min, once per week) with afterwards presented to the school’s head of studies for approval. no overlap in terms of content. This programme also included Three of the initial seven interested secondary education centres teachings, daily simple exercises, visualisations and specific were committed to the study requirements (i.e. schedules and practices to promote relaxation and increase the student’s time students’ randomisation); two of them were public schools and management ability, considered a strong predictor of academic the other one was private. Both the students and their families performance (Mercanlioglu, 2010; Aeon et al., 2021). The or legal guardians were offered information about the study relaxation exercises were based on Jacobson’s techniques (Schwarz via an informative meeting and an email answering frequently and Schwarz, 2017). A session-by-session description of the asked questions, along with the informed consent; those who intervention can be found elsewhere (Delgado Suárez, 2020). signed the document were included in the study. The baseline measures were assessed before randomisation, which was conducted by a member of the research team who Measures Nonviolent Attitudes and Behaviours was not related to this project using Epidat 4.2. Following the The Attitudes Toward Social Aggression Scale (ATSAS; De La methods used in previous randomised controlled trials implying Villa Moral, 2005) is a 48-item self-report measure to assess teenagers (Johnstone et al., 2016), the study conditions remained attitudes towards violence and harassment among teenagers. It blind for the participants, although the nature of the intervention includes 3 subscales which represent the primary outcomes of was clear after some sessions. Both interventions were delivered the present study: (1) cognitive dimension, consisting of 14 in parallel in each high school, and they were conducted by items that assess the students’ perceptions about using violence, external professionals. After 8 weeks, the post-treatment both physical and verbal, towards their classmates (e.g. ‘violence assessment was conducted, and a 4-month follow-up assessment is the last resort’); (2) affective dimension, which includes 8 was also performed; this last evaluation was supposed to items that examine the degree of identification or rejection that be conducted after 6 months, but the restrictions derived from both aggressors and victims generate in the teenager (e.g. ‘I do the COVID-19 pandemic in the first semester of 2020 forced not want to have violent friends’); and (3) behavioural dimension, the research team to adapt the schedule and, anticipating a which consists of 26 items and refers to behavioural dispositions possible advance of the end of the school year, the follow-up and previous experiences related to violence (e.g. ‘I avoid taking assessment was conducted in April 2020 via SurveyMonkey. part in fights’). Each item was answered in a Likert-type scale (1 = ‘Strongly disagree’, 5 = ‘Strongly agree’). The scores of the Interventions subscales ranged from 14 to 70 for the cognitive dimension, ‘Unlearning’ from 8 to 40 for the affective dimension and from 26 to 130 This programme consists of a weekly 45–50 min session for for the behavioural dimension. Higher scores indicate higher 8 weeks conducted by a health professional with specific formation levels of aggressive attitudes. The questionnaire was developed in mindfulness and compassion-based interventions. The in Spanish and presented good psychometric properties, including programme includes teachings, daily simple exercises, high internal consistency (α = 0.89; De La Villa Moral, 2005). meditations, visualisations and specific practices to augment the teenagers’ ability to be considerate and kind towards Mindfulness themselves and others and to increase present-focused attention. The Child and Adolescent Mindfulness Measure (CAMM; Greco A more detailed description of the intervention can be found et al., 2011) is a 10-item self-report questionnaire that assesses in Delgado Suárez (2020). mindfulness in children and teenagers. Each item (e.g. ‘I pay ‘Unlearning’ was designed by the research group considering close attention to my thoughts’) is answered using a Likert Crane et al. (2017) standards for mindfulness-based interventions scale (0 = ‘Never true’; 4 = ‘Always true’); the total score ranges and pedagogic recommendations for implementing mindfulness from 0 to 40, with higher scores reflecting higher levels of in educational contexts, such as offering interactive, experiential, mindfulness. The Spanish version of the CAMM has presented student-based learning (Santorelli, 2000). Regarding the study good psychometric properties, including adequate internal population, some adaptations were made so the programme was consistency (α = 0.82; Turanzas, 2013). easily followed by teenagers: explicit teaching of abilities, interactive methods based on teenage-related experiences and facilitating resources for implementing mindfulness and compassion in the Self-Compassion daily life (Kuyken et al., 2013). In addition, some parts of the The Self-Compassion Scale-Short Form (SCS-SF; Raes et al., programme were synthetised and more attention was granted 2011) is a 12-item on five-point Likert scale (0 = ‘Almost never’ Frontiers in Psychology | www.frontiersin.org 3 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers to 5 = ‘Almost always’) to record how often the respondent The primary analysis consisted of the evaluation of the behaves kindly and caringly towards themself in difficult life efficacy of ‘Unlearning’ compared to the active control condition situations (e.g. ‘I try to be loving towards myself when I’m for promoting nonviolence; the primary outcomes were the feeling emotional pain’). This questionnaire is an adaptation ATSAS’ subscales, which were taken as continuous outcomes. from the original SCS (Neff, 2003). The present study only A repeated measures design was performed with an intention used the global SCS-SF score, which is calculated by taking to treat basis using multilevel mixed effects linear regression the average score of the 12 items; it ranges from 0 to 5, with models, including time as an independent variable and subjects higher scores reflecting higher levels of self-compassion. The and the group of delivery (subgroup) as random effects, focussing Spanish version of the SCS-SF has shown high internal consistency our interest at the individual (student) level. Restricted maximum (α = 0.86; Garcia-Campayo et al., 2014). likelihood estimation was used, which produces unbiased estimates in case of small or unbalanced sample sizes (Egbewale Data Analysis et al., 2014). Non-standardised slopes and 95% confidence Sociodemographic data were described at baseline by means of intervals (CI) were calculated. Effect sizes were assessed using frequencies or means. A visual inspection and the corresponding Cohen’s d statistic, calculated by the combined standard deviation Chi-squared or Student’s t tests were conducted to ascertain the in the baseline, weighing the differences between the equal distribution of sociodemographics among groups at baseline. corresponding marginal means (Morris, 2008). Effect sizes are FIGURE 1 | Flow chart of participants in the randomised controlled trial. Frontiers in Psychology | www.frontiersin.org 4 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers TABLE 1 | Sociodemographic characteristics of the sample and baseline levels of nonviolence, mindfulness and compassion. Baseline Characteristics of the Sample The sociodemographic characteristics of the sample are presented Unlearning Relaxation in Table 1. No significant differences were appreciated between t/χ2 (p) the ‘Unlearning’ group and the control group in any of the (n = 81) (n = 83) variables. Regarding the baseline levels of the study variables, Sociodemographic characteristics no significant differences were observed between the groups. A table of correlations has been included as Supplementary Material. Sex, n (%) Female 44 (54.3%) 47 (56.6%) 1.97 (0.211) Male 37 (45.7%) 36 (43.4%) Effects on the Primary Outcomes Age, mean (SD) 13.78 (1.09) 13.78 (1.10) 0.03 (0.975) The within-group analyses (Table 2) indicated that ‘Unlearning’ School, n (%) did not produce any significant effect on the primary outcomes Public 64 (79%) 64 (77.1%) 0.09 (0.851) post-test nor in 4-month follow-up. The relaxation programme Private 17 (21%) 19 (22.9%) showed a significant intragroup effect in the ATSAS ‘Cognitive’ Year of studies, n (%) subscale, as a significant increase in the score was observed in 2nd 40 (49.4%) 40 (48.2%) 0.09 (0.958) the follow-up (t = 2.34, p = 0.021), although the effect size was 3rd 17 (21%) 19 (22.9%) small (d = 0.25), and this result was not significant after applying 4th 24 (29.6%) 24 (29.9%) the Benjamini-Hochberg correction. The other ATSAS subscales Study variables did not present significant effects. The mixed effects model indicated that both interventions were equivalent regarding the ATSAS, M (SD) primary outcome in every time point, although a tendency close Cognitive 32.74 (7.83) 32.56 (7.56) 0.98 (0.328) to statistical significance was observed in the ‘Behavioural’ subscale Affective 29.78 (5.24) 30.22 (5.38) −0.53 (0.597) Behaviour 56.11 (12.87) 54.47 (14.10) 0.78 (0.438) in favour of ‘Unlearning’ (t = 1.81, p = 0.073, d = 0.61; Table 3). CAMM, M (SD) 13.90 (6.78) 14.25 (6.15) −0.34 (0.735) SCS-SF, M (SD) 2.83 (0.85) 2.91 (0.95) −0.53 (0.601) Effects on the Secondary Outcomes ATSAS = Attitudes Toward Social Aggression Scale, CAMM = Child and Adolescent The within-group analyses (Table 2) indicated that ‘Unlearning’ Mindfulness Measure, SCS = Self-compassion scale. produced a significant effect post-test in self-compassion (t = 3.68, p < 0.001) of small effect size (d = 0.38). In the follow-up assessment, that effect was maintained (t = 3.65, p < 0.001, d = 0.40), usually defined as small when d = 0.2; medium when d = 0.5; and a significant increase in mindfulness was observed (t = 7.08, and large when d = 0.8 (Cohen, 1988). The efficacy of the p < 0.001), which presented a large effect size (d = 0.85). The interventions regarding the SDQ, the CAMM and the SCS-SF relaxation programme did not produce any significant effect was calculated following the same analytical strategy used for post-test, but only a significant increase in mindfulness in the the primary analysis. Within-group analyses were also performed follow-up (t = 6.09, p < 0.001) with a moderately large effect for both primary and secondary outcomes. size (d = 0.73). An alpha level of 0.05 was set, using a two-tailed test. The intergroup analyses (Table 3) reflected significant We applied the Benjamini-Hochberg correction for multiple differences between the two study arms in self-compassion comparisons (Glickman et al., 2014). Data analyses were both post-test (t = −2.48, p = 0.014, d = 0.45) and in the 4-month computed using IBM SPSS v26.0 statistical software. follow-up assessment (t = −2.03, p = 0.044, d = 0.41), but both effects lost statistical significance after applying the Benjamini- Hochberg correction. RESULTS Participant Flow and Compliance DISCUSSION A total of 182 students from three secondary education centres The results of the present study indicate that the sample conformed the initial sample, although some of them did not presented relatively low baseline levels of aggressive attitudes meet the inclusion criteria (see Figure 1). Therefore, the final in the cognitive and the behavioural dimensions (De La Villa sample consisted of 164 high school students which were Moral, 2005); that would imply that teenagers tended to believe randomised to ‘Unlearning’ (n = 81) or relaxation (n = 83). Most things such ‘violence is the last resort’ or ‘those who are violent of the participants attended all the sessions in both programmes end up being rejected by others’ and that they usually acted (83.5%). In the ‘Unlearning’ group, 79 (97.5%) participants in a non-impulsive, peaceful way. These low baseline levels provided post-test data, and 75 (92.6%) students performed could have been in part responsible of the lack of effect of the 4-month follow-up assessment. For the active control group, ‘Unlearning’ in these dimensions. Regarding the active control the retention rates were 97.6% post-test and 89.2% at follow-up, group, a statistically significant increase in the cognitive which did not represent significant differences between dimension of social aggression was observed in the follow-up, the groups. although the effect size indicated that it was small, and it was Frontiers in Psychology | www.frontiersin.org 5 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers TABLE 2 | Raw scores and intragroup differences per group. Baseline Post-test Follow-up Walda LR testb Baseline vs. Post-test Baseline vs. Follow-up M (SD) M (SD) M (SD) χ2df (p) χ2df (p) d B (95% CI) t (p) d B (95% CI) t (p) ‘Unlearning’ 1.0 (2) 105.7 (2) 0.58 0.05 ASTAS 31.56 (7.56) 32.10 (8.70) 31.17 (8.57) 0.85 (0.394) 0.07 0.00 −0.02 (0.986) Cognitive (0.063) (<0.001) (−0.69 to 1.85) (−1.28 to 1.38) ATSAS 1.1 (2) 128.0 (2) −0.46 37 30.22 (5.38) 29.76 (5.76) 29.95 (5.54) 0.09 −0.98 (0.327) 0.07 −0.76 (0.447) Affective (0.574) (<0.001) (−1.37 to 0.45) (−1.31 to 0.56) ATSAS 2.0 (2) 140.5 (2) 0.43 −1.38 54.47 (14.10) 54.97 (18.14) 52.44 (16.06) 0.05 0.35 (0.726) 0.17 −1.12 (0.265) Behaviour (0.371) (<0.001) (−2.09 to 2.95) (−3.99 to 1.22) 61.4 (2) 26.6 (2) 0.18 5.84 CAMM 14.25 (6.15) 14.44 (5.87) 19.99 (6.93) 0.03 0.23 (0.819) 0.85 7.08 (<0.001) (<0.001) (<0.001) (−1.42 to 1.77) (4.20 to 7.48) 16.6 (2) 62.0 (2) 0.34 0.36 SCS-SF 2.91 (0.95) 3.24 (0.89) 3.25 (0.91) 0.38 3.68 (<0.001) 0.40 3.65 (<0.001) (<0.001) (<0.001) (0.15 to 0.54) (0.16 to 0.56) Relaxation ASTAS 5.5 (2) 140.4 (2) 0.91 1.76 32.73 (7.83) 33.78 (7.76) 34.36 (8.71) 0.14 1.36 (0.176) 0.25 2.34 (0.021)* Cognitive (0.617) (<0.001) (−0.50 to 2.33) (0.29 to 3.23) ATSAS 4.4 (2) 102.5 (2) −0.84 −0.91 29.78 (5.24) 28.96 (5.33) 28.97 (5.31) 0.15 −1.81 (0.074) 0.17 −1.85 (0.067) Affective (0.110) (<0.001) (−1.76 to 0.09) (−1.88 to 0.07) ATSAS 3.1 (2) 140.8 (2) 1.57 1.77 56.11 (12.87) 57.90 (14.25) 57.32 (14.52) 0.19 1.33 (0.185) 0.23 1.44 (0.153) Behaviour (0.216) (<0.001) (−0.55 to 3.68) (−0.48 to 4.01) 36.2 (2) 65.5 (2) 1.58 5.05 CAMM 13.90 (6.78) 15.30 (6.55) 18.92 (9.25) 0.23 1.88 (0.062) 0.73 6.09 (<0.001) (<0.001) (<0.001) (−0.04 to 3.19) (3.38 to 6.72) 0.8 (2) 74.5 (2) 0.02 0.08 SCS-SF 2.83 (0.85) 2.84 (0.87) 2.88 (0.93) 0.02 0.19 (0.847) 0.08 0.78 (0.438) (0.700) (<0.001) (−0.16 to 0.19) (−0.10 to 0.26) *statistically not significant after applying the Benjamini-Hochberg correction; Significant effects are presented in bold. ATSAS = Attitudes Toward Social Aggression Scale, CAMM = Child and Adolescent Mindfulness Measure, SCS = Self-compassion scale. M = mean. SD = standard deviation. aOmnibus test. bModel fit of the mixed model. d = effect size. B (95% CI) = regression coefficient (95% confidence interval). t(p) = t test (value of p). not significant after applying the Benjamini-Hochberg correction; hinder the generalisation of these findings. In view of these thus, this should be studied in future studies before considering results, it could be possible that mindfulness-based interventions it a relevant result. On the other hand, the affective dimension could be more efficacious for reducing negative attitudes than presented relatively high baseline levels of social aggression, for enhancing positive ones, at least in what refers to personal reflecting that the students presented tendencies to feel admiration beliefs and behaviours. towards those who know how to insult or to enjoy violent Another aspect that could explain the lack of effect of movies. This had already been reported by De La Villa Moral ‘Unlearning’ could be its format. Salmoirago-Blotcher et al. (2005), who found that insulting or threatening could (2019) implemented a mindfulness-based programme which be perceived by adolescents as a form of asserting social status lasted longer and included more sessions per week and found in a group. No significant effects were observed in this dimension that the programme was more efficacious than an intervention after the interventions, post-treatment nor in the 4-month addressed to enhancing resilience and self-esteem, among others; follow-up assessment. however, the effects were not maintained in a 6-month follow-up This is not the first study to observe lack of effects of assessment, which reflects that the efficacy of the intervention mindfulness-based interventions on aggressive attitudes; for was limited to the short term. This leads to wonder if mindfulness- instance, Wongtongkam et al. (2015) found that their based programmes are the best approach for reducing aggressive mindfulness programme was not superior to an inactive attitudes among adolescents; although there are some control group for reducing violent behaviours among university methodological shortcomings, there is a significant number of students. On the other hand, some studies which focused studies indicating that different programmes (not mindfulness- on specific samples, such as teenagers with severe behaviour related) produce significant reductions in bullying and problems (Franco et al., 2016), oppositional defiant disorder victimisation rates (Ttofi and Farrington, 2011). However, it (Nelson-Gray et al., 2006) or hyperactivity (Singh, 2016), has been observed that the efficacy of anti-bullying programmes found positive results for the mindfulness programmes. In decreases notably in teenagers older than 13 (Villanueva Badenes these cases, the interventions were efficacious compared with et al., 2013; Yeager et al., 2015), and in some cases, adverse an inactive control group, but the methodological shortcomings effects (i.e. increasing aggressive attitudes) have been reported Frontiers in Psychology | www.frontiersin.org 6 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers TABLE 3 | Between-group analyses for primary and secondary outcomes (ITT approach). Unlearning Relaxation Walda LR testb Unlearning vs. Relaxation Outcomes M (SD) M (SD) χ2df (p) χ2df (p) d B (95% CI) t(p) Primary ATSAS-Cognitive 9.6 (5) 244.6 (2) (14–70) (0.087) (<0.001) Baseline 31.56 (7.56) 32.73 (7.83) Post-treatment 32.10 (8.70) 33.78 (7.76) 0.19 0.33 (−1.54 to 2.19) 0.34 (0.729) Follow-up 31.17 (8.57) 34.36 (8.71) 0.37 1.76 (−0.34 to 3.87) 1.65 (0.101) ATSAS Affective 6.6 (5) 233.3 (2) (8–40) (0.250) (<0.001) Baseline 30.22 (5.38) 29.78 (5.24) Post-treatment 29.76 (5.76) 28.96 (5.33) 0.15 −0.38 (−1.68 to 0.92) −0.57 (0.566) Follow-up 29.95 (5.54) 28.97 (5.31) 0.19 −0.54 (−1.91 to 0.83) −0.78 (0.439) ATSAS Behaviour 7.1 (5) 284.2 (2) (26–130) (0.217) (<0.001) Baseline 54.47 (14.10) 56.11 (12.87) Post-treatment 54.97 (18.14) 57.90 (14.25) 0.34 1.15 (−2.16 to 4.46) 0.68 (0.494) Follow-up 52.44 (16.06) 57.32 (14.52) 0.61 3.15 (−0.29 to 6.60) 1.81 (0.073) Secondary CAMM (0–40) 98.2 (5) 93.3 (2) (<0.001) (<0.001) Baseline 14.25 (6.15) 13.90 (6.78) Post-treatment 14.44 (5.87) 15.30 (6.55) 0.15 1.36 (−0.95 to 3.67) 1.16 (0.247) Follow-up 19.99 (6.93) 18.92 (9.25) 0.17 −0.85 (−3.16 to 1.47) −0.72 (0.471) 24.8 (5) 135.5 (2) SCS-SF (0–5) (<0.001) (<0.001) Baseline 2.91 (0.95) 2.83 (0.85) Post-treatment 3.24 (0.89) 2.84 (0.87) 0.45 −0.33 (−0.59 to −0.07) −2.48 (0.014)* Follow-up 3.25 (0.91) 2.88 (0.93) 0.41 −0.28 (−0.56 to −0.01) −2.03 (0.044)* *statistically not significant after applying the Benjamini-Hochberg correction; Significant effects are presented in bold. ATSAS = Attitudes Toward Social Aggression Scale, CAMM = Child and Adolescent Mindfulness Measure, SCS = Self-compassion scale. M = mean. SD = standard deviation. aOmnibus test. bModel fit of the mixed model. d = effect size. B (95% CI) = regression coefficient (95% confidence interval). t(p) = t test (value of p). after the interventions (Cerezo Ramírez and Sánchez Lacasa, more than active control conditions (Huppert and Johnson, 2010; 2013; Campbell et al., 2019). All in all, promoting nonviolence Schonert-Reichl and Lawlor, 2010; Tharaldsen, 2012; Rawlett among teenagers constitutes a difficult challenge for educators. et al., 2019). Some of these authors have suggested that adolescents Including the students’ families, the teachers and the community may not have developed yet the abilities to successfully integrate could be an aspect of higher relevance for a programme to and apply mindfulness skills that have been trained in relatively be effective and finding ways to act not only in class but also short periods of time. Moreover, mindfulness programmes could in the teenager’s home is also needed. lead to experience frustration among teenagers, as they encourage For what concerns to the secondary outcomes, the intragroup them to be aware of negative common thoughts and feelings analysis suggests that ‘Unlearning’ significantly promoted instead of avoiding them. Interestingly, meta-analytic results mindfulness, although only in the follow-up assessment, but with suggest that mindfulness-based interventions seem to be more a large effect size. The active control condition also produced effective for teenagers with clinical conditions than for the general significant improvements in mindfulness in the follow-up, with population (Zenner et al., 2014; Zoogman et al., 2015; Dunning a moderate effect size. Thus, the intergroup analyses indicated et al., 2019), which could be reflecting that, as abovementioned, that ‘Unlearning’ did not produce significant effects compared these programmes could be more efficacious for reducing negative to the relaxation programme in mindfulness, which suggests that tendencies in targeted sub-groups rather than improving positive both interventions promote improvements in mindfulness skills ones, as some authors have suggested (Quach et al., 2016). or that maybe these changes are due to maturation effects related On the other hand, ‘Unlearning’ seemed to produce a to the passage of time. Previous studies have already found that significant improvement in self-compassion compared to mindfulness programmes do not improve mindfulness in teenagers the relaxation programme, both post-treatment and after Frontiers in Psychology | www.frontiersin.org 7 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers 4 months, although these effects were not significant after previous authors have suggested regarding mindfulness possibly applying the correction for multiple comparisons. Improving not being the best approach for addressing these issues self-compassion could be a very positive outcome since it among adolescents. could have major implications for the teenagers, not only in their aggressive attitudes, but also on very common problems they face, such as self-judgment, mood changes DATA AVAILABILITY STATEMENT and loneliness feelings (Bluth et al., 2016b; Pullmer et al., 2019). A compassion-based programme named ‘Making The raw data supporting the conclusions of this article will friends with yourself ’ produced significant improvements be made available by the authors, without undue reservation. compared with an inactive control group in self-compassion in a sample of 34 teenagers (Bluth et al., 2016a), and the authors observed a potential buffering effect of self- ETHICS STATEMENT compassion in protecting adolescents from social stressors (Bluth et al., 2016b). However, in line with our results, The studies involving human participants were reviewed and the meta-analysis conducted by Wilson et al. (2019) found approved by Comité de Ética de la Investigación de la Comunidad that compassion-based programmes had significant effects Autónoma de Aragón (CEICA): PI18/299. Written informed on self-compassion, although not when compared to active consent to participate in this study was provided by the control conditions. participants’ legal guardian/next of kin. Some limitations of the present study need to be acknowledged. First, the sample was formed by teenagers from one city (Zaragoza, Spain), and the high schools were AUTHOR CONTRIBUTIONS not randomly selected, which limits the external validity of our results. Also, no students of the 1st year of secondary ID-S: substantial contributions to the conception and design education were included due to schedule incompatibilities. An of the work, data acquisition, data analysis, and interpretation important aspect to be considered is the use of self-reported of results. YL-d-H and JG-C: substantial contributions to the measures, which imply a certain bias, and the lack of a more conception and design of the work and contributions to revising objective measure of aggressive behaviour (e.g. classroom conflict the work critically for important intellectual content. AP-A log and expulsions for misconduct); the effect of social desirability and JM-M: substantial contributions to data analysis and in the answers of the ATSAS could be a possible reason behind contributions to drafting and revising the work critically for the low baseline levels of aggressive attitudes in our sample. important intellectual content. MM-A, MB-R, and SG: In this regard, the ATSAS, despite being a validated instrument, contributions to drafting and revising the work critically for could have been complemented with other measures for a important intellectual content. All authors agreed to be better characterisation of the violent/nonviolent attitude (Olweus, accountable for the content of the work. 1996; Cajigas et al., 2004). In the same line, mindfulness, which is generally considered a multifaceted construct, could have been assessed using more complete and extensive measures. FUNDING Finally, regarding the interventions that were applied in the present study, there was no information in relation to home ID-S had a FPU predoctoral contract awarded by the Spanish practice, which is a key element for mindfulness and compassion- Ministry of Education, Culture and Sports to the Institute of based programmes to be effective. Health Research of Aragon (IIS) in Zaragoza, Spain (FPU16/03565). AP-A has a ‘Sara Borrell’ research contract from the Instituto de Salud Carlos III (CD20/00181). This research was funded CONCLUSION in whole, or in part, by the Welcome Trust (JM-M; 104908/Z/14/Z). This research is funded by a FIS grant from the Carlos III This study found that the mindfulness and compassion-based Health Institute of the Ministry of Spain Economy and programme ‘Unlearning’ was not effective for reducing aggressive Competitiveness (PI19 / 00805), DGA group (B17-20R) and attitudes in teenagers. Some dimensions of these attitudes the Network for Prevention and Health Promotion in Primary already presented low baseline levels, which probably hindered Care (RD16 / 0007 / 0005) grant from the Carlos III Health the efficacy of the interventions. ‘Unlearning’ improved self- Institute of the Ministry of Economy and Competitiveness compassion, although not in a significant manner compared co-financed with ERDF funds from the European Union. to the active control group; focusing on this outcome may contribute to help adolescents in dealing with some of the most common emotional problems they have to face. The SUPPLEMENTARY MATERIAL studies conducted on this topic agree on the complexity of measuring nonviolence and the necessity of including teachers The Supplementary Material for this article can be found and families in programmes addressed at promoting it. Moreover, online at: https://www.frontiersin.org/articles/10.3389/fpsyg.2021. the lack of effect of ‘Unlearning’ could go in line with what 717736/full#supplementary-material Frontiers in Psychology | www.frontiersin.org 8 December 2021 | Volume 12 | Article 717736 Delgado-Suárez et al. Cultivating Nonviolence Among Teenagers Glickman, M. E., Rao, S. R., and Schultz, M. R. (2014). False discovery rate REFERENCES control is a recommended alternative to Bonferroni-type adjustments in health studies. J. Clin. Epidemiol. 67, 850–857. doi: 10.1016/j.jclinepi.2014.03.012 Aeon, B., Faber, A., and Panaccio, A. (2021). Does time management work? Greco, L. A., Baer, R. A., and Smith, G. T. (2011). Assessing mindfulness in A meta-analysis. PLoS One 16:e0245066. doi: 10.1371/journal.pone.0245066 children and adolescents: development and validation of the child and Bluth, K., Gaylord, S. A., Campo, R. A., Mullarkey, M. C., and Hobbs, L. adolescent mindfulness measure (CAMM). Psychol. 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The use, distribution or reproduction in other forums is permitted, provided 7, 27–56. doi: 10.1007/s11292-010-9109-1 the original author(s) and the copyright owner(s) are credited and that the original Turanzas, J. (2013). Adaptación Transcultural de la Escala CAMM (Child and publication in this journal is cited, in accordance with accepted academic practice. Adolescent Mindfulness Measure) y estudio preliminar de sus características No use, distribution or reproduction is permitted which does not comply with psicométricas. master’s thesis. Valencian International University. these terms. Frontiers in Psychology | www.frontiersin.org 10 December 2021 | Volume 12 | Article 717736