Alcohol Use in Spanish Youth

Substance use in young people is one of the problems that most concerns today's society (^{Moreno et al., 2016}). Of all substances, alcohol is the most socially accepted in daily life and the most prevalently used drug in Spain across all ages (Delegación del Gobierno para el Plan Nacional sobre Drogas [^{DGPND, 2017}]). According to official reports in 2017, in Spain 36.5% of population older than 15 use alcohol habitually and 29% occasionally (Instituto Nacional de Estadística [^{INE, 2017]}). Among youth aged 15-24, 36% report having been drunk in the last year (^{DGPND, 2017}), 11.9% report an episode of heavy drinking in the last month (^{INE, 2017}) and 7.2% who answered the AUDIT scale met criteria for high risk alcohol consumption (DGPND, 2017). More specifically to adolescents, results from the Drug Use Survey in Secondary Education in Spain (Observatorio Español de las Drogas y las Adicciones [^{OEDA, 2019]}) indicate that most of those aged 14-18 have consumed alcohol at least once in their lifetime (77.9%) and also in the last month (58.5%). In that study, 32.3% of students reported having had an episode of heavy drinking and 24.3% reported having been drunk, both in the last month.

Alarmingly, more than half of 14 year old students (56.1%) reported having consumed alcohol in the last year and 36% had consumed alcohol in the last month (^{OEDA, 2019}). These reports are consistent with research that indicates that alcohol is the most widely used substance in Spain, including the most prevalent substance used in mid-adolescence. Some studies estimate the general mean age for initiation of alcohol consumption at 16.6 years old (^{DGPND, 2017}). Other studies specify the mean age of first alcohol consumption at 14.0 years old and the mean age of a weekly alcohol use at 15.2 years old (^{OEDA, 2019}). All these large, national studies show a relatively stable tendency in the prevalence of consumption as well as ages for initiating alcohol use. The early onset and widespread prevalence of alcohol use among youth in Spain is a critical situation that research and public policies should address.

Therefore, prevention becomes essential to delay the onset of consumption and avoid habitual alcohol consumption in adolescence. In Spain, from the Government Delegation for the National Plan on Drugs (PND), the National Strategy on Addictions 2017-2024 establishes the guiding principles of evidence, social participation, intersectorality, integrality, equity, and gender (^{PND, 2017}). Above all, the need for evidence-based prevention programs is emphasized. Several programs have been developed at the intervention-prevention level to avoid or reduce substance use or other problematic behaviors among young people, and their effectiveness has been evaluated (e.g., ^{Gómez-Fraguela et al., 2003}; ^{Moral et al., 2009}; ^{Orte et al., 2013}). However, in order to determine the effectiveness of a prevention or intervention program, it is necessary to carry out a systematic and thorough evaluation processes in each specific context. Within this framework, the Mantente REAL program (originally Keepin' it REAL; ^{Marsiglia & Hecht, 2005}) has been adapted to several cultural contexts and has been tested to assess its effectiveness.

Mantente REAL as an Effective Prevention Program

Mantente REAL is a school-based universal prevention program targeting drug use and other problematic behaviors specifically designed to be implemented at the beginning of adolescence and thus prevent early substance use. The program has been developed, implemented, and evaluated in the United States by an interdisciplinary team from the Global Center for Applied Health Research at Arizona State University. In its original version (2005), Keepin' it REAL proved effective in preventing substance use by middle school students in Arizona (^{Hecht et al., 2003}) and was evaluated as one of the three most cost-effective school-based substance use prevention programs (^{Miller & Hendrie, 2008}). Linguistically and culturally adapted versions of the program have also been implemented and evaluated in several Spanish-speaking countries, such as Guatemala, Mexico, Spain, and Uruguay (^{Kulis et al., 2019}; ^{Marsiglia et al., 2018}; ^{Marsiglia et al., 2019}).

Mantente REAL is a program with an innovative and efficient design that brings together the fundamental elements of evidence-based prevention programs for adolescents (^{Tobler et al., 2000}), elements that are separated or absent in other implemented programs in Spain. The 12 lessons are implemented during the school year as part of students' regular academic curriculum, which facilitates the integration of content and learning. Moreover, the program aims at preventing substance use generally and at alcohol, tobacco, and cannabis use specifically, but also includes content related to other pressure situations typical in adolescence; therefore, it indirectly addresses antisocial behavior that could be perpetrated as a result of peer pressure. Furthermore, the program is not simply focused on strengthening socio-emotional skills, but also addresses the decision-making and risk assessment processes as well as specific behavioral strategies for dealing with risky situations and how to find social support if needed; that is, it teaches life skills. In addition, Mantente REAL is a prevention program being implemented in other countries which allows cross-cultural comparisons that would help advance knowledge on substance use prevention.

The program focuses on a generic skill training through which students acquire concrete social pressure resistance skills to not engage in alcohol and other drug use or other antisocial behaviors (^{Alberts et al., 1991}; ^{Gosin et al, 2003}; ^{Moon et al., 1999}). The main purpose of the program is to teach students how to resist substance use offers and opportunities, such as offers of alcohol, tobacco, and other drugs, using the REAL strategies (refuse, explain, avoid, and leave). Refuse refers to the ability of saying "No" in a clear, direct, and respectful manner, either verbally or non-verbally. Explain is to give one or more reasons to decline the offer. Avoid consists of not going to places, situations, or with people where alcohol or drugs might be offered or available. Leave refers to exiting situations where alcohol or drugs are offered or present. These are strategies used most commonly by youth who successfully resist using substances (^{Kulis et al., 2011}; ^{Marsiglia et al., 2009}).

The program combines the acquisition of the REAL strategies with other personal and social skills that play an essential role in the psychological adjustment and psychosocial development of adolescents (e.g., communication, assertiveness, risk assessment, and problem solving skills) (^{Sancassiani et al., 2015}). Learning these skills has a special relevance in adolescence since this constitutes a critical stage in psychosocial development, especially in terms of susceptibility to social influence (^{Steinberg, 2017}). In order to reinforce learning and facilitate the incorporation of these strategies in the behavioral repertoire, the skills training of Mantente REAL are drawn from the adolescents' context, the skills are based on the youths' communication and decision-making processes. In this regard, the viewing of videos based on the cultural norms of adolescents, scripted, and acted by students, is part of the curriculum of the program (^{Holleran et al., 2002}). Therefore, Mantente REAL is made by young people for young people.

The process to adapt Mantente REAL to Spain focused on modifying the curriculum manuals for teachers and students and the accompanying videos and to make them more representative and realistic for the context of contemporary Spanish adolescents. This process started with a linguistic adaptation of the Spanish version of Mantente REAL that was created for Mexico (^{Marsiglia et al., 2019}), by updating the language to usage in Spain and incorporating gendered language and typical youth idioms and expressions. All new professionally directed videos were created to introduce the program and represent the four REAL drug resistance strategies. The video scripts were developed and enacted by youth from the target population to represent authentic situations where Spanish adolescents confront behavioral health risks, such as drug offers, in identifiably Spanish locations. Examples of behavioral risk scenarios in the curriculum manuals were also adapted and revised to reflect the Spanish cultural context. All the changes in content were supervised and reviewed by independent experts in the field of prevention. The adaptation process maintained fidelity to the contents of the original program by retaining the core elements of the program, such as the mastery of the four drug resistance strategies and training in risk assessment and communication competence.

Research thus far has shown the program to be effective for the prevention of substance use in different contexts and countries. Several studies have demonstrated the significant effects of Mantente REAL in reducing adolescent substance use (alcohol, tobacco, and cannabis), preserving or increasing negative attitudes towards substance use, strengthening norms against substance use, and increasing the use of effective drug resistance strategies (^{Kulis et al., 2005}; ^{Kulis et al., 2019}; ^{Marsiglia et al., 2015}). As regards gender differences in the effectiveness of Mantente REAL, previous research conducted in Mexico indicated that although gender differences in adolescent alcohol use have narrowed to near parity the effects of the program on alcohol frequency are moderated by gender, with females showing stronger desired effects than shown by males (^{Marsiglia et al., 2015}). Despite the evidence in other Spanish-speaking contexts, no research has previously tested the effectiveness of the Spanish version of Mantente REAL adapted to Spain. Previous evidence suggests that the degree to which the curriculum is culturally adapted can affect the program's effectiveness (^{Griner & Smith, 2006}; ^{Kulis et al., 2005}). Therefore, the effectiveness of the culturally adapted version of Mantente REAL to Spain should be tested.

The Current Study

As one more phase of the described process, the current study aims to evaluate at the quantitative level the effectiveness of the culturally adapted version of Mantente REAL with a sample of Spanish adolescents. Although data about tobacco and marijuana use were also collected, this study specifically tests effects on alcohol outcomes. Since it is the most socially accepted and the most prevalently used drug in Spain, this study aims specifically to assess several types of alcohol use, considering different measures that range in severity. Three main hypotheses are proposed. First, that Mantente REAL would be effective in reducing the rates of (a) frequency of alcohol use, (b) amount of alcohol used, (c) heavy drinking episodes, and (d) intoxication episodes. Second, that Mantente REAL would be more effective with students at greater risk, as proposed by the risk argument (^{MacKinnon et al., 1989}), that is, adolescents experiencing higher levels of alcohol use would show stronger desired effects of the Mantente REAL program than those less involved with alcohol use. Third, that Mantente REAL would be equally effective in females and males. Given the pervasive presence of alcohol in the Spanish context and the high rates of consumption among Spanish adolescents, the implementation of a validated program such as Mantente REAL represents important progress in the field of school based prevention. Thus, the findings of this study would contribute to advancing the availability of culturally specific and evidence based alcohol prevention programs in Spain.

Participants

The sample was composed of 755 Spanish adolescents aged 11 to 15 (M = 12.24, SD = 0.56), 47.1% females, residing within two different regions: Santiago de Compostela (Galicia, NW Spain; n = 347) and Seville (Andalucia, S Spain; n = 408); 40.1% of adolescents were born in Galicia, 50.3% in Andalucia, 3.4% in another part of Spain, and 6.1% in another country. Almost a half of students lived with 3 other persons at home (45.5%). Students mostly reported their parents have a level of education equal to or higher than high school (61.2%) and always have enough money at home for food, transportation, utilities, school fees, and clothes (60.9%). Table 1 shows sociodemographic characteristics of the sample by intervention condition. Adolescents were enrolled in the 1^st grade of compulsory secondary education in the school year 2018/2019 in 12 state secondary schools, 6 in the region of Santiago and 6 in the city of Seville. Schools were selected by convenience sampling, but randomly assigned to the experimental or control conditions. Figure 1 displays the study's CONSORT diagram, showing the school selection process and the flow of participating students (enrollment of subjects, assignment to intervention conditions, and retention of subjects during the study).

Table 1.  Sociodemographic Characteristics of Participants, by Intervention Condition 

Note. Cramer's V is the effect size of chi square differences (categorical variables) and Cohen's d is the effect size of t-test differences (continuous variables).

Figure 1.  CONSORT Diagram for Spain Mantente REAL Efficacy Trial 

Instruments

Recent alcohol use. Four different measures of alcohol use in the past 30 days were evaluated (^{Graham et al., 1984}; ^{Hansen & Graham, 1991}). Adolescents reported their frequency of alcohol use (1 item, "In the last 30 days, how many times have you had an alcoholic drink?"), the amount of alcohol used (1 item, "In the last 30 days, how many alcoholic drinks have you had?"), as well as the frequency of heavy drinking episodes (1 item, "In the last 30 days, how many times did you drink five or more alcoholic drinks in a row (– on the same ocassion?") and intoxication episodes (1 item, "In the last 30 days, how many times have you got drunk?"). Responses were scored from 0 to 6 for the frequency measures (none, only once, 2-3 times, 4-9 times, 10-19 times, 20-39 times, 40 times or more) as well as for the amount measure (none, part of one, entire, 2-3, 4-9, 10-19, 20 or more). Questions were phrased identically at the pre-test and the post-test.

Intervention condition. A dummy variable was created to contrast the students who received the Mantente REAL curriculum (1) with the students in the control group who did not receive the Mantente REAL curriculum (0).

Control variables. Intervention effects were estimated while controlling for three variables assessed in the pre-test: gender, intervention site, school belonging, and parenting practices. These variables were included to control for differences between samples from the two regions in the students' reports on their school and family environments, and the potential influence of these psychosocial factors on student's responsivity to the program. Gender was assessed by the dummy variable female (0) versus male (1). A dummy variable was created to control for site, contrasting Santiago de Compostela (1) versus Seville (0). Students' sense of school belonging was assessed by the question "Do you feel part of this school?" answered in a 4-point scale (not at all, a little, some, very much). A principal component factor score was created to control for parenting practices combining a scale of positive relationship with parents (6 items; e.g., "You think your parents care about what you feel"; α = .86; ^{Upchurch et al., 1999}), a scale of parent-child conflict (8 items; e.g., "You think you and they get along badly"; α = .87; ^{Robin & Foster, 1989}), and a scale of parental knowledge of the child's whereabouts and activities (3 items; e.g., "They know what you do after school"; α = .81; ^{Kerr & Stattin, 2000}), all of which students answered in a 4-point scale (never, few times, sometimes, many times).

Risk moderation interactions. To test whether the Mantente REAL program would be more effective in students already involved with alcohol use (students who showed higher rates in the pre-test), four interaction variables were created by multiplying the dummy variable for the intervention condition by the mean-centered value of each dependent variable at the pre-test (i.e., frequency, amount, heavy drinking, intoxication).

Gender moderation interaction. To test whether Mantente REAL would be equally effective in females and males, an interaction variable was created by multiplying the dummy variable for the intervention condition by the dummy variable of gender.

Procedure

Compliance with ethical standards was taken into account throughout the research and the project was approved by the Bioethics Committee of the University of Santiago de Compostela and the University Pablo de Olavide. The study was first presented to the heads of 46 secondary schools (see CONSORT diagram, Figure 1), who were provided with the necessary information about the study, in the cities of Seville and Santiago de Compostela. Given that Santiago de Compostela is a city with a smaller population than Seville, schools in the outskirts of Santiago de Compostela were also considered to take part in the study. Since the objective was to carry out a pilot study, a sample close to 800 participants was targeted; that is, considering the mean number of students enrolled in Spanish schools, a total of 12 schools were the sample target. Therefore, the recruitment ended once 12 secondary schools agreed to participate in the study, six in each site.

To guarantee the validity of the study, selected schools were randomly assigned to control and experimental groups. Thus, six schools (three in each site) were assigned to the experimental group (i.e., with Mantente REAL implemented in the 1^st grade) and the other six (three in each site) were assigned to the control group (i.e., the program is not implemented). In the schools assigned to the experimental group the program was implemented by the regular tutors (homeroom teachers) in their classrooms during school hours. The program adapted to Spain has a total of 12 lessons that were to be implemented weekly. Program implementation was structured and guided by a teacher's manual, which detailed all the activities and procedures to follow, and a student's workbook, which contained the activities to be completed by students. Before starting the curriculum's lessons, all 1^st grade tutors in the intervention schools received practical training over a two day long session to learn how to deliver the Mantente REAL curriculum with fidelity. In the schools assigned to the control group no other prevention programs were being implemented during that school year, only the regular activities included in the students' curriculum.

In order to evaluate the effectiveness of the program, information regarding variables of interest was collected in all 12 schools, before (pretest) and after (posttest) the implementation of the program in the experimental group. Posttest surveys were administered approximately four months after the pretest. In addition, two sources of qualitative data were collected: fidelity observations (3 observation sessions) during the program implementation and focus groups with teachers and students after the implementation to assess challenges in delivering the program and the degree of satisfaction with it. Thus, the evaluation process of the program followed the recommendations of some authors (^{Fernández et al., 2002}), who proposed to use a quantitative and qualitative methodology. For quantitative data collection, qualified members of the research teams visited the centers, explained the objectives of the research, and provided proper instructions to the adolescents who answered the self-reported questionnaires. Parental consent was requested and, subsequently, adolescent assent was obtained before questionnaires were administered. Adolescent participation was voluntary, and anonymity and confidentiality of information were completely guaranteed. A confidential unique code created by students themselves was used to match pre-tests and post-tests. This method resulted in a low rate of sample attrition (see CONSORT diagram, Figure 1): 89.9% of the pre-tests had a matched post-test.

Data Analysis

IBM SPSS Statistics 24 and MPLUS 7 were used to conduct the statistical analyses. Baseline (pre-test) equivalence on sociodemographic characteristics was tested across intervention conditions. We assessed equivalence with chi-square tests, t-tests, and standardized effect size measures (Cramer's V or Cohen's d), using the value .10 as the threshold of imbalance between groups (^{Austin, 2009}). If variables showed significant standardized differences across conditions (> .10), they were included as control variables in further analyses in order to control for their potential influence on the program's effectiveness. Second, frequencies, skewness, means, and standard deviations were analyzed and changes in the outcome variables from pre-test to post-test were examined with pairwise t-tests, within and between intervention conditions, to show the direction and statistical significance of the changes. The intervention effect size was estimated using Cohen's d, dividing the difference-in-differences between experimental and control groups by the pooled standard deviation of the raw scores within groups. Next, three different linear models were analyzed in MPLUS for each outcome: 1) a general model to assess the intervention effects using the dummy variable contrast of intervention condition; 2) the general model including risk moderation interactions for each outcome to test whether the intervention was more effective in the students who were already more or less involved with alcohol use in the pre-test; and 3) the general model including the gender moderation interaction to test whether the intervention was equally effective in female and male students. All tests adjusted statistically for the school-level clustering of data (Mplus "Cluster" command) and type = complex was specified to take non-independence of observations into account. All models controlled for the outcome as measured at the pre-test, gender, intervention site, parental education level, school belonging, and parenting practices. In addition, all models employed full-information maximum likelihood (FIML) estimation to account for attrition to the post-test (10.1%) and item missing data, as well as the robust maximum likelihood (MLR) estimator to adjust for non-normal and zero inflated distributions in alcohol use.