'Keepin' It REAL in Mexico: An Adaptation and Multisite RCT Implementation of a Substance Abuse Prevention Curriculum for Adolescents in Three Mexico Cities.
'Keepin' It REAL in Mexico: An Adaptation and Multisite RCT Implementation of a Substance Abuse Prevention Curriculum for Adolescents in Three Mexico Cities.
Sharp increases in substance use rates among youth in Mexico are a major concern, both in
 Mexico and the US. Although the Mexican government has elevated substance abuse prevention as
 a national priority, there are few school-based universal prevention programs to choose from
 that are culturally grounded, empirically tested, and shown to be efficacious. This study
 aims to address this gap by adapting, implementing, and testing the keepin' it REAL (kiR)
 prevention intervention in Mexico's three largest cities: Mexico City, Guadalajara, and
 Monterrey. kiR is a model program for middle school students on the US National Registry of
 Effective Programs and Practices, shown to be efficacious and cost-effective in reducing
 substance use among large multi-ethnic and Mexican American samples in the US. The proposed
 study will leverage the bi-national research team's expertise in developing and adapting kiR
 and build upon a series of feasibility studies across Mexico which showed that kiR's core
 elements are applicable there. However, evidence also suggested that further adaptation is
 needed to enhance the intervention's cultural fit. During the proposed study's Phase 1,
 students and teacher-implementers in three schools-one from each of the cities-will provide
 feedback about the original curriculum and identify culturally and contextually relevant
 scenarios and examples. The bi-national research team-including original kiR curriculum
 designers-will collaborate to ensure cultural applicability in Mexico and fidelity to core
 elements of kiR. In Phase 2, the efficacy of the culturally adapted Mexican version of kiR,
 relative to the original version of kiR and to a control condition, will be tested through an
 intent-to-treat analysis in a randomized controlled trial with 7,768 7th grade students in 36
 middle schools, 12 from each city. The study will investigate and incorporate into the
 curriculum gender specific experiences with drug offers and appropriate drug resistance
 strategies in the Mexican context that may impact the youths' risk of substance use and their
 responsiveness to prevention programs. In light of rising violence in Mexico, a secondary aim
 of the study is to investigate how youths' perpetration, victimization, and witnessing of
 violence may moderate the efficacy of kiR in Mexico. The study will create knowledge relevant
 to efficacious prevention approaches for Mexican-heritage youth on both sides of the
 US-Mexico border. Prevention science will be advanced by understanding how culturally
 influenced gender norms affect substance use offers, attitudes, and behaviors, as well as the
 success of universal prevention programs. In addition, the study will add to knowledge on how
 to execute collaborative, cross-national, translational prevention intervention research.
The need for more effective prevention efforts in Mexico is clear and increasingly urgent,
 with important ramifications for the US. In the US immigrant adolescents from Mexico
 historically have had lower drug use rates than US-born Mexican Americans, but these trends
 are changing rapidly. To fill the gap in evidence-based universal prevention programs in
 Mexico, this study proposes to adapt, implement, and test the efficacy of kiR-a school-based
 substance use prevention program in use in the US and several other countries-among a sample
 of youth from the three largest urban areas in Mexico. This study will directly impact
 factors influencing sustainability - leadership, capacity, and relationship building. The
 research team is partnering with Dr. Medina-Mora and the National Psychiatric Institute of
 Mexico, which oversees substance use prevention nationwide. This study will build long-term
 relationships with Mexican scientists, educators, government agencies, social workers, and
 community stakeholders; demonstrate the feasibility of coordinated strategies for
 implementing school-based prevention programs involving national and local stakeholders; and
 will increase the capacity of schools and communities to deliver future interventions to
 additional students.

 keepin' it REAL (kiR), a SAMHSA recognized model program on the National Registry of
 Effective Programs and Practices (NREPP), is a school-based, manualized curriculum for
 substance use prevention among middle school students. The kiR curriculum includes: 10 weekly
 classroom lessons; 5 videos demonstrating drug resistance strategies that were scripted,
 acted and filmed by students; and school-wide booster activities (e.g., replaying the videos)
 to reinforce the classroom lessons. The curriculum is implemented by regular classroom
 teachers who receive a two-day long training.

 The curriculum includes the mix of elements found to have the largest effect sizes in
 school-based prevention interventions: those that teach comprehensive life skills to increase
 knowledge of substance use, address affective and motivational aspects of substance use
 (e.g., anti-drug attitudes, beliefs and values) and build risk assessment, decision making,
 and drug refusal skills. kiR emphasizes the mastery and expansion of a repertoire of the drug
 resistance strategies most commonly and effectively employed by adolescents: to refuse
 substance offers with a simple "no", to explain or provide an excuse to decline the offer; to
 avoid situations where substances might be offered; and to leave when substances are offered.
 kiR teaches a variety of communication techniques to reject risky or undesirable influences,
 and the flexibility to select appropriately from a repertoire of strategies in different
 situations. Youths equipped with multiple strategies can assess situations where substances
 are offered, decide which resistance strategies will be most effective, and try additional
 strategies (repertoire) if the first one does not work.

 There are several reasons the original kiR curriculum is an appropriate foundation for
 developing efficacious school-based prevention approaches in Mexico: its attention to Mexican
 American cultural and social contexts of substance use; evidence of the applicability of
 kiR's core components in Mexico; and its ideal developmental timing for implementation. There
 are also theoretical and empirical reasons that additional adaptation to the cultural and
 social contexts of Mexico is needed. The cultural communication patterns of youth and the
 context of substance use offers needs to be incorporated when adapting it for use in Mexico.

 Cross-sectional studies in Mexico show that kiR's core elements and approach are relevant and
 effective for Mexican youth from different regions. Surveys of Mexican high school youth
 found that kiR strategies were not only used in Monterrey and in Guanajuato State, but that
 the use of these strategies is associated with decreased alcohol and tobacco use. A
 longitudinal randomized pilot field trial of kiR in two Guadalajara middle schools reported
 significant effects in reducing use of alcohol, cigarette, and marijuana use, but in ways
 that differed for males and females, suggesting that additional tailoring of the curriculum
 to gendered substance use cultural and social contexts may be needed.

 In addition to testing the efficacy of kiR in Mexico, the potential moderating influence of
 gender role norms and violence will be explored. Despite rapid cultural changes in gender
 socialization in Mexico and women's attainment of higher levels of education and workplace
 participation, traditional gender role norms for women continue to be influential. Young
 women adhering to more traditional gender role norms also tend to use substances less because
 females are more closely monitored by parents, more restricted to the home, and less exposed
 to risky environments such as unsupervised parties or bars. However, among the growing
 proportion of female adolescents in Mexico who are questioning traditional gender role norms,
 these cultural restraints are lessening and the risk of substance use is growing. Female and
 male adolescents in Mexico are nearing parity in rates of alcohol use, although females still
 report less use. Norms for men that promote hyper-masculinity, aggressiveness and
 impulsiveness encourage behaviors like heavy drinking and risky sex that have severe health
 consequences. The persistence of traditional male gender role norms underscores the pressing
 need for effective drug resistance strategies that provide male adolescents with ways to
 counterbalance unhealthy cultural messages with positive cultural norms.

 Gender differences among adolescents in Mexico have been reported in the use of the REAL drug
 resistance strategies, in the association between use of these strategies and actual
 substance use, and in the effects of kiR in a pilot feasibility field trial in Guadalajara.
 While both males and females used the REAL strategies to resist substance use offers, the
 relationship between substance use and the use of REAL strategies was either stronger for
 males than for females or only significant for males. The field trial found short-term
 effects in reducing females' use of alcohol and cigarettes and in the long-term use of
 alcohol, while desirable effects for males were found for long-term use of marijuana.

 The pervasive violence in some Mexican communities has the potential to influence youths'
 vulnerability to using substances and the effectiveness of strategies to prevent or resist
 substance use. Experiencing violence as a perpetrator, victim, or witness is a complex and
 interconnected phenomenon. Among urban minority youth in the US, 95% of perpetrators also
 report violence victimization or witnessing community violence. Although an investigation of
 the mechanisms linking violence to youth substance use is beyond its scope, the proposed
 study will investigate how youths' perpetration, victimization, and witnessing of violence
 may moderate the efficacy of kiR.

 This is a highly innovative study which will conduct the first national RCT of a school-based
 and evidence-based universal prevention intervention that is systematically culturally
 adapted for Mexico, using a NREPP model program. The proposed cultural adaptation design is
 innovative because it includes a bi-national team of stakeholders: students, teachers, school
 administrators, and researchers participating on an equal footing throughout the adaptation
 and testing phases. Second, the study advances knowledge on the transferability to emerging
 economies of prevention interventions that were developed, implemented, and tested in the US
 and based on a science of prevention. Third, the study will investigate and incorporate the
 gendered nature of substance use risk in the design of an adapted universal prevention
 program, and assess the differential efficacy of the program on male and female adolescents
 who adopt more and less traditional gender role norms in a societal context where those norms
 are rapidly changing. Fourth, the study will examine if Mexican adolescents experiencing
 different types of violence (exposure, perpetration, and victimization) derive differential
 benefits from universal school based substance use prevention programs like kiR. Fifth, a
 bi-national research team with a long-standing history of collaboration and productivity will
 lead the study, bringing together leading scientists in prevention in Mexico with the
 original designers of the kiR intervention.

 The ASU-based research team has a long trajectory starting in the 1990s related to the
 original development, testing, sub-group analysis, and dissemination of kiR. Over more than a
 decade, the research team has conducted three exploratory studies across different regions of
 Mexico in order to advance understanding of the social and cultural contexts of substance use
 among Mexican youth and the bi-national applicability of kiR. Study 1. A cross-sectional
 study conducted in Monterrey, Mexico with 327 students in two high schools (grades 10-12)
 demonstrated: the use of the REAL strategies to resist alcohol, tobacco and marijuana offers;
 gender differences in use of the strategies; and an inverse relationship between use of the
 strategies and actual substance use. Study 2. Similar findings emerged in a larger
 probability-based sample conducted in Guanajuato (State) with 702 students in eight high
 schools. The Monterrey and Guanajuato studies provided initial evidence that the use of REAL
 strategies is associated with less substance use among Mexican youth; however, the studies
 did not directly address the effectiveness of kiR in a Mexican cultural context. Study 3. To
 test the cultural fit of kiR in Mexico and to prepare for possible adaptation of the program
 to the Mexican context, a longitudinal randomized pilot feasibility trial was conducted in
 Guadalajara, Mexico with 432 middle school students in two schools. In this study, kiR was
 implemented with only minor linguistic adaptations (e.g. English-to-Spanish translation,
 Spanish dubbing of videos) and showed promising signs of effectiveness. The intervention had
 significant short-term effects in reducing females' use of alcohol and cigarettes, and the
 long-term use of alcohol, and desirable effects for males were found for long-term use of
 marijuana.

 The proposed study design is guided by communication competency theory and aims at testing
 the main hypothesis that by incorporating elements of the social and cultural contexts in
 which children live, prevention interventions will be more efficacious. Phase 1 (2 years):
 Aim 1, in this adaptation phase, the original kiR will be implemented in one school each in
 Guadalajara, Mexico City, and Monterrey. Students will participate in guided discussions and
 focus groups assessing the applicability in the Mexican context of the curriculum lessons'
 examples, substance offer scenarios, and drug resistance strategies. Implementing teachers
 from all sites will also complete feedback forms after each lesson and meet later in focus
 groups to discuss the implementation of the curriculum and suggest revisions. Student and
 teacher focus groups will be transcribed and analyzed to identify recurring themes and
 recommendations. Project Coordinators from each site and developers of the original
 curriculum will meet to decide on and incorporate revisions of the original curriculum to
 ensure cultural relevance. Special attention will be given to scenarios related to gender
 differences in drug offers and appropriate responses to them. Phase 2 (3 years): Aims 2, 3 &
 4, a longitudinal RCT of the adapted version of kiR will be conducted in 36 public middle
 schools in Guadalajara, Mexico City and Monterrey, with schools randomized within each city
 into three conditions: (A) culturally adapted kiR, (B) original kiR, and (C) control. In
 addition to questions relating to substance use and its psychosocial antecedents, pretest
 (T1), post-test (T2) and long-term follow-up surveys (T3) will assess traditional gender role
 norms and violence (victimization, perpetration and witnessing).

 The curriculum will be modified through a targeted adaptation process in which the original
 kiR is implemented in translated form in one school in each study site. Prior to program
 initiation, implementing teachers will receive training provided by the site Project
 Coordinators, the Mexican co-PI and supported by ASU master trainers. After each weekly
 lesson of the curriculum, students will complete a short curriculum feedback form and then
 participate in group discussions facilitated by a project team member and recorded. This will
 allow the research team to identify and address cultural and practical barriers to
 implementation and areas that need to be adapted or changed. State and local educational
 authorities as well as school principals will be invited to participate in the teachers'
 focus groups to identify system level issues with implementation, dissemination and
 sustainability.

 After curriculum feedback data have been collected, transcribed, and analyzed, Project
 Coordinators from each site will meet with members of the original US curriculum development
 team to incorporate the examples and scenarios provided by students. Core components of the
 curriculum will be preserved, e.g. overall structure, topics, and skills training in the use
 of the REAL strategies. During the curriculum adaptation process, the study's Bi-National
 Scientific Leadership Team led by the Mexican co-PI will review and approve suggested changes
 to ensure the cultural applicability and preservation of core components of kiR.

 After the adaptation is complete, the randomized control trial will be conducted in
 Guadalajara, Mexico City, and Monterrey, with 12 schools from each site assigned at random
 into three conditions: (A) culturally adapted kiR, (B) original kiR (translated only), and
 (C) control. All students will complete a pretest survey before the start of the intervention
 (T1) and post-tests to assess short-term (T2) and long term (T3) program effects on substance
 use behaviors and antecedents (drug use intentions, norms and attitudes), and drug resistance
 strategies.

 Sites, Schools, and Participants. The Mexico City, Monterrey, and Guadalajara metropolitan
 areas will serve as the three sites for the study. These sites were chosen as the largest
 metropolitan and economic hubs in Mexico (accounting for over a fourth of the Mexican
 population), as major sending communities to the US, and as prime destinations or stop-overs
 for migrants coming from rural Mexico, Central and South America, many on an intended
 migration path to the US. From these three sites, the sample of 7th grade children will be
 drawn from 36 public schools (Total N ≈ 7,768). The nine schools within each site will be
 randomized into conditions A, B and C, three schools per condition. Implementation in each
 site will be led by the research partners in México: 1) Instituto Nacional Psiquiatrico de
 México - Ciudad de México, 2) Universidad Autónoma de Nuevo León, and 3) Instituto Milton
 Erickson Guadalajara.

 Participant Recruitment. At the beginning of the school year, schools will distribute a
 general "letter-to-parents" that describes the study. About a week later, and with the
 schools' assistance, a letter to the 7th grade parents will be sent home via the children.
 This letter will again describe the study but will also invite parents to indicate if the
 child will not participate. Children whose parents do not want the children to participate
 will be excluded from all surveys. Children whose parents do not opt out will be randomized
 according to the treatment condition assigned to the child's school.

 Data Collection. Data collection will be the responsibility of the Mexican research partners,
 assisted by data collection, instrumentation, and quality assurance protocols developed by
 the US research team. A baseline pretest survey (T1) will be administered to consented 7th
 grade students at all sites at the start of the school year and before the beginning of kiR.
 The 10-lesson intervention will begin immediately after. An initial post-test (T2) will be
 administered two months after implementation ends (the end of 7th grade), at a time when the
 program effects on short-term psychosocial antecedents of substance use (e.g., drug-related
 intentions, norms,and attitudes) are expected to be strongest. An additional follow-up
 posttest (T3) will be administered one year later, at the end of 8th grade, to assess the
 long-term efficacy of the intervention. Fidelity measures will be collected during
 implementation. Project team members will observe implementation on a standardized schedule
 to ensure fidelity to kiR program.

 Participant Database and Tracking. The Mexican research partners will enter the data at each
 site and securely transfer it to the US research team. The US team will develop a database
 using REDCap which will track youth throughout the RCT. Unique identifiers will allow for
 matching across survey waves. The database will contain the participant's name, unique
 identifier, and site, school and teacher when first entering the study. Participant tracking
 through REDCap has been used successfully in previous studies by the team.

 Process Evaluation Measures. In the adaptation phase, teacher and student written feedback
 after each lesson will be self-reported on lesson feedback forms, using instruments and
 measures initially developed for the original kiR trial.

 In the RCT phase, the process of recruitment of the schools in the three cities will be
 documented to capture challenges and solutions. Fidelity is captured by items assessing the
 implementer's adherence to the program manual when delivering the lesson's key
 components-instructions, video, practice, and homework-as well as the implementer's
 enthusiasm, preparedness, implementation self-efficacy, and program acceptance (implementer
 comfort using program).

 Survey Measures. Key measures in the survey instrument are connected to communication
 competence theory to assess the repertoire of drug resistance strategies that the students
 use in different social and cultural contexts and how each may influence substance use.
 Traditional measures of substance use behaviors and the psychosocial antecedents were chosen
 for internal consistency over time through prior evaluations of kiR and use in other
 prevention trials, and are supplemented by measures of gender role norms and experience of
 violence. Table 1 summarizes key measures and psychometric properties. Spanish language
 back-translated versions of most items were employed successfully in the research team's
 preliminary pilot Mexico studies in Monterrey, Guanajuato, and Guadalajara (see Section C1).
 Prior to employing the questionnaire items in the proposed RCT, the items will be tested
 during the Phase I pilot test in three schools, one in each city, to reconfirm suitability,
 accurate translation, and psychometric properties.

 Substance Use Behaviors: Key student outcomes include the youths' self-reports of recent
 (last 30 days) frequency and amount of substance use (alcohol, cigarettes, marijuana, and
 inhalants). While no independent validation of actual substance use will be obtained through
 biochemical measures, there is sufficient evidence of the validity of self-reports under the
 proposed conditions: comparing self-reports over time and across treatments, focusing on
 recent substance use, and using administrative procedures that minimize bias (e.g.,
 establishing rapport, insuring confidentiality, placing sensitive questions toward the end).

 Substance Use Antecedents: Key psychosocial antecedents of substance use will be assessed as
 program outcomes to test whether the kiR intervention reinforces important protective factors
 against substance use: substance use intentions, attitudes (positive expectancies of
 substance use), antidrug norms (personal, injunctive, and descriptive), and drug offer
 refusal confidence (or efficacy). A 3-item measure will assess the students' intentions to
 accept offers of alcohol, cigarettes or marijuana if offered to them the coming weekend. The
 positive substance use expectancies measure assesses perceptions of the positive consequences
 of substance use, e.g. whether using substances makes it easier to be part of a group,
 reduces nervousness, or makes parties more fun. Substance use personal norms will be gauged
 by asking: "Is it OK for someone your age to..." "drink alcohol," "smoke cigarettes," or
 "smoke marijuana". The injunctive drug norms items measure expected negative or positive
 reactions by parents and best friends to the respondents' use of substances. The items ask
 how angry the students' parent(s) would be if they found out that the student "smoked
 marijuana," "smoked cigarettes," or "drank alcohol", and how best friends would act towards
 them if they used the same substances. Two descriptive norms items (perceptions of the extent
 of substance use among age peers) ask respondents to estimate the proportion of school peers,
 and of friends, who have tried alcohol, cigarettes, and marijuana. Refusal confidence is
 measured by three items that ask the extent to which the student is sure that he or she would
 decline an offer of alcohol from a family member, of marijuana from a close friend, and of a
 cigarette from a school peer.

 Drug Resistance Strategies: The drug resistance strategies measures will assess students'
 responses to actual and hypothetical substance use offers: the frequency or likelihood of
 turning down an offer by "just saying no" (refuse); give an explanation or excuse (explain);
 stay away from situations where people the same age are using substances (avoid); leave the
 situation (leave); or some other resistance strategy. These items will be posed in two ways:
 as questions about resistance strategies actually used in the last 30 days, and as likely
 responses in a hypothetical situation, being offered a beer at a party next weekend.

 Gender Role Norms: Adherence to traditional gender role norms will be measured by the
 five-item Gender Roles subscale of the Mexican American Cultural Values Scales for
 Adolescents. The scale assesses adolescents' beliefs in having distinct roles for males
 (bread-winner and head of household) and females (child-rearing and protecting daughters).
 The subscale was validated and shown reliable with a sample of 750 fifth grade
 Mexican-heritage males and females in the Southwestern US.

 Exposure to Violence: A modified version of the Exposure to Violence and Violent Behaviors
 Committed checklists will be used to measure middle-school students' violence perpetration
 and violence victimization in the home, school, and neighborhood context. A modified 10-item
 subscale of Things I Have Seen and Heard will assess exposure to community violence.

 Demographics and Controls: Finally, a set of socio-demographic and control questions will
 include gender, usual academic grades, age and birth date (the latter useful for verifying
 tracking and matching across waves), and family and household composition. Socioeconomic
 status will be measured by utilizing information about the educational attainments of the
 respondents' parents and reports of household financial strain.

 Process Evaluation Analysis. The goal of the process evaluation in the adaptation phase is to
 identify further adaptations that are necessary to refine kiR for use in Mexico. The process
 will involve assembling, extracting, coding and comparing information from the open-ended
 discussion group and focus group data, and lesson feedback provided by students and teachers.
 Investigators will follow strategies that are designed to increase the rigorousness of
 analysis and interpretations including triangulation, analyst cross-checking, and an audit
 trail. Overall assessments of the salience of these patterns will then inform decisions about
 cultural adaptations to kiR that should be incorporated into the revised Mexican version of
 the curriculum.

 RCT Program Efficacy Analyses. Student questionnaire data will be employed to test hypotheses
 about the efficacy of the adapted kiR curriculum, using intent-to-treat analyses comparing
 all students at pretest who were in condition A schools with (1) students in condition B
 schools, and with (2) students in condition C schools. Prior to conducting hypothesis tests,
 measures will be assessed for adequate variability and scale reliability, and exploratory
 factor analysis will be employed in data reduction. For the hypothesis tests, the dependent
 variables will include T2 and T3 post-test measures of the outcomes listed above in section
 C5.

 Hypothesis 1. Program efficacy: students receiving the culturally adapted version of kiR will
 report relatively lower undesirable outcomes (e.g. recent substance use, intentions to use
 substances) and relative increases in desirable outcomes (e.g. anti-drug personal norms and
 attitudes, use of REAL strategies) when compared to students receiving the original kiR
 (translated only) and those in the control group.

 Hypotheses 2a, b. Gender role norms as moderators: The efficacy of the intervention will vary
 for males and females who differ in adherence to traditional gender role norms.

 Hypothesis 3. Violence as a moderator: The intervention will produce stronger desired effects
 among youth who report more experience of violence (as victim, perpetrator, or witness).
 These youth may benefit more from the intervention because of being at higher risk for using
 substances.

 Investigators will use both baseline adjusted general linear model procedures (i.e., variants
 of multiple regression) and growth curve modeling to test Hypothesis 1 concerning program
 efficacy. The first method will predict short-term (T2) and then long-term (T3) post-test
 outcome measures (substance use, antecedents, and drug resistance strategies) with dummy
 variable contrasts of intervention conditions, while controlling simultaneously for the
 baseline pre-test (T1) measure of the particular outcome. Condition A (adapted kiR) will be
 compared with Condition B (original kiR) and then compared in a separate analysis with
 Condition C (Control). Growth curve models will test whether and how changes over time in the
 outcomes (trajectories from T1 to T2 to T3) differ significantly by these same contrasts of
 conditions. Hypotheses 2a, 2b and 3 will be tested employing mean centered interactions of
 the measures of traditional gender role norms and experience of violence with the dummy
 variable contrasts of study conditions (A v. B, A v. C). Prior to these tests of moderation
 investigators will check the applicability of the assumption under the risk moderation
 argument that substance use behaviors (measured before intervention) vary according to
 traditional gender role norms and experience of violence as described in sections A5 and A6.
 The data will be analyzed using multilevel statistical models (e.g., SAS Proc Mixed), with
 individual students clustered within schools, to adjust for any school-level random effects
 that may result in biased standard errors. All analyses will introduce controls for the
 metropolitan site of the intervention and any demographic characteristics of participants
 that are shown to differ significantly across sites at the pretest.

 Missing Data, Attrition and Retention Strategies. As in any longitudinal study, there is
 likely to be attrition and item missing data, but our preliminary research suggests that it
 will be readily manageable with available statistical techniques. Investigators will employ
 multiple imputation methods to adjust for missing data, which have been used successfully in
 studies of prevention program efficacy. Using the PROC MI procedure in SAS, creating multiple
 complete datasets, analyze them with complete-data methods, and combine the results of these
 analyses to arrive at a single estimate that properly incorporates the uncertainty in the
 imputed values. The number of imputations will be adjusted, as recommended.

 Statistical Power. The sample size of 7,768 students within 36 schools was determined through
 a power calculation to be able to detect small to medium effect sizes. A minimal expected
 effect size of 0.15 for main outcomes was determined through the Guadalajara pilot
 feasibility study and prior US-based studies testing adaptations of kiR. Interclass
 correlations (ICCs) were calculated using data from the original RCT of kiR in 35 schools in
 the Southwestern US (Note: with only two schools, ICCs could not be calculated in the
 Guadalajara pilot feasibility study). Among the twelve main outcomes, the highest ICC was
 0.02. Thus, given an ICC of 0.02, an effect size of 0.15, and a moderately effective pretest
 that explains 60 percent of the between school variation, our design has 0.80 power with 12
 schools per treatment, 150 students per school (n = 7,768). Power was calculated for a
 two-level cluster randomized design using RDPOWER.

 Over the last decade the US research team has systematically developed research partnerships
 with colleagues in different regions of Mexico to better understand the substance use needs
 of Mexican youth and to test the applicability of kiR in the Mexican cultural and social
 context. These partnerships have also enriched the team's work in the US with Mexican
 American youth. The proposed study is a natural outgrowth of these bi-national
 collaborations. Mexican researchers who have collaborated with the US team on prior pilot
 studies in Mexico will also participate in the proposed study, advancing the partnership and
 enhancing prevention research capacity in Mexico.

 Responsibilities for completing the research will be shared by the Mexican and US research
 teams. Dr. Medina-Mora will serve as the Mexican Co-PI and will oversee the quality assurance
 procedures including fidelity and research protocols. Dr. Medina-Mora is a national and
 international distinguished researcher and Director of the National Psychiatric Institute of
 Mexico. The three teams of Mexican researchers will be responsible for recruitment and
 retention, collection of process evaluation and student survey data, and data entry at each
 respective site. The US research team will design the protocols for data collection,
 instrumentation, and quality assurance, and conduct the statistical analyses of program
 efficacy and tests of hypotheses. Both the US and Mexican teams will be involved in the
 curriculum adaptation process, interpretation of findings, manuscript development and
 dissemination activities.
Inclusion Criteria:

 -  all students enrolled in participating class rooms

 Exclusion Criteria:

 -  n/a