Study design and participants.
This was a cluster randomized controlled pilot study. Our target sample was vulnerable Santiago schools, with students from low- to low-middle-income families. Our sample frame was the registry of schools with primary education (Year 1 to Year 8) located in Santiago, with a vulnerability index (School Vulnerability Index – National System of Equality Allocation (IVE-SINAE)) ≥ 70%. The IVE-SINAE is built considering several students’ and parental variables: health, family income, and receiving state benefits. This percentage means the proportion of students in a school who are most needed.
The study population consisted of students attending Year 6 (around 12 years old), 7, and 8 (about 14 years old). We target adolescents aged 12-14 because this is when adolescents start experimenting with drugs (especially smoking and alcohol) and because this was the age range of students included in the original evaluation of Unplugged in Europe (30, 31).
Inclusion criteria for schools
1. To have at least two classes in the grade under study.
2. To be a mixed-sex school. Most of the schools in Chile are in this condition.
3. To accept participation under the conditions of the study. Mainly to accept being part of the control group after randomization.
Exclusion criterion
Schools implementing other interventions with strong and manualized packages targeted at the same grades.
Ethical issues
Data were collected following the Declaration of Helsinki. This study was approved by the ethics committee CEC201734 (08/07/2018).
Procedure
First, we reviewed the records of schools provided by the Ministry of Education (MINEDUC) that met the inclusion and exclusion criteria (n=126). We contacted schools until we reached the aimed number (n=6). Fourteen schools were contacted by telephone, email, or personally. Of these, two refused to participate in the study, six did not give any response, and six agreed.
Randomization and allocation
Once the schools agreed to participate in this research, they were randomly allocated to 1) the YSLQQ group or 2) the Control Group. The randomization was carried out by an independent statistician using the platform www.random.org. After this allocation, each school was informed of the assigned group, and the research group started coordinating the sending of the written and informed consent to parents and caregivers, scheduling the baseline assessment, and, for the YSLQQ group, organizing the training for school staff.
Blind Condition
In this research, schools, facilitators, and training staff were not blind to the group allocation because of the nature of the intervention. However, evaluators and the statistician who conducted the final analyses were blinded.
Intervention Group: “Yo Se Lo Que Quiero”
Adaptation process
The “Unplugged” preventive program was designed based on the Comprehensive Social Influence Model (32, 33), incorporating the educational approach to life skills and normative beliefs about drugs. This program aims to delay the onset of drug use and the transition from occasional to habitual use. It is focused on tobacco, alcohol, and marijuana consumption. This program was adapted following the guidelines in the literature on replicating evidence-based prevention programs in new contexts and the discussion on the deep and surface structure of interventions (34, 35). The deep structure of intervention includes the intervention theory of change. According to the leading theories of the social influence approach (social learning and social norms), drug use initiation results from social influence, from which adolescents can derive erroneous perceptions of frequency and acceptability of use. Normative education and resistance skills training included in Unplugged curricula are thought to reduce the effect of social influence by modifying attitudes, beliefs, and normative perceptions, finally supporting the development of general social skills and skills to resist social pressures. The intervention surface structure consists of the parts that improve the face validity of the intervention with participants, language, material, activities, and communication channels. Researchers stress maintaining the deep structure while allowing surface structure modifications in new contexts. The degree of this adaptive change can vary from minimal to complete adaptation (35). We decided to define a minimally adapted edition of the Unplugged program with only surface structure changes. The deep structure of Unplugged remained unchanged in the Chilean version. The surface structure of the Unplugged materials was screened by two psychologists of our research group together with one teacher. This screening showed that the intervention materials and activities were acceptable and culturally relevant, with only minimal changes necessary. The original European developers were informed about all the modifications proposed for the Chilean version, which was approved. Specific modifications to the materials involved changes in the language, pictures included in the materials, and some stories used during the student lessons.
Furthermore, some modifications were made to the implementation model due to differences between the European and Chilean school systems and teachers' workload in schools. First, the implementation schedule was different because the Chilean school system has different timing compared to Europe, starting in March and ending in December. Second, school teachers in the Chilean system feel that the workload is very high, and they consider it to be challenging to be responsible for implementing the curriculum by themselves; therefore, the program was implemented by facilitators. These facilitators were educators hired and trained by the research team. Additionally, ensuring the implementation follows a high fidelity and adherence to the manual was very important. To ensure the fidelity of the implementation, we provided supervision to the facilitators, which consisted of weekly face-to-face meetings during the school year (2 h each) with the research team to prepare lessons and to monitor the implementation, and a direct line (phone and e-mail) to discuss and solve specific problematic situations or doubts. Finally, in Chile, a certain number of school teachers change schools across the years, and they know in which class they will be only at the end of February before the school year starts. This is one of the reasons for scheduling teachers, facilitators, and school staff training in February in the Chilean schools.
YSLQQ Curriculum
The program consists of 12 45-minute sessions taught weekly by previously trained facilitators. Briefly, the curriculum is taught using interactive techniques. It aims to develop and enhance personal and social skills (critical and creative thinking, relationship skills, assertiveness, refusal skills, verbal and non-verbal communication, managing emotions, coping skills, empathy, problem-solving, and decision-making skills) with a specific focus on normative education (e.g., the correction of normative beliefs about substances and of the incorrect perception of the prevalence of use among peers). The titles of the 12 sessions are as follows: (1) What is I Know What I Want?, (2) Inside or outside the student group, (3) Alcohol; risks and protection, (4) Will it be as you think?, (5) What to expect from tobacco?, (6) With your own voice, (7) Assert yourself in the face of pressure, (8) On stage!, (9) ) Know more, risk less, (10) Strategies to face difficulties, (11) Solve problems and face decisions, (12) Establish objectives. For more information regarding each session, see Supp 1.
The training consisted of a 3-day workshop held by Chile's Unplugged master trainer coupled with the master trainer of the EU-Dap Faculty in February 2019. All sessions are reviewed in the training, and 4 of them are executed by the training participants. Chile´s Unplugged master trainer modeled two sessions; the rest were examined in depth. The objective of the training is to exemplify an experiential program through modeling activities.
The school curriculum was taught in the selected Chilean schools from Abril to November 2019. To standardize the implementation of the program, a Teacher Manual, an adequate number of quiz card sets, and a Student Booklet were provided to teachers and students.
Recruitment of facilitators
The facilitators were educators hired by the research team trained to apply the intervention. Facilitators have had at least 2 years of experience working in the classroom. They participated in the 3-day workshop.
Supervision of facilitators
The facilitators were supervised by the team coordinator in weekly meetings in which the implementation of the content of each of the sessions, the methodological strategies used, and the problems that arose were reviewed.
Control Group
The control group received the usual teaching activities regarding substance use prevention, which were implemented in the schools as a usual practice.
Outcomes
Primary Outcome
Acceptability, feasibility, fidelity and quality of implementation
Acceptability
Acceptability was assessed by establishing how this intervention program was received by the students and to what extent this intervention responds to the needs of this target population. In particular, acceptability was assessed through a questionnaire answered by each student who participated in the intervention. This questionnaire included five sections related to the perception and experience lived in the sessions (4 items), implementation of the program "YSLQQ" (5 items), effects and usefulness of the YSLQQ program (7 items), satisfaction with YSLQQ (4 items), and satisfaction with the duration of the sessions (3 items), each of these questions had a Likert scale (1 “Strongly disagree” to 5 “Strongly agree”). Additionally, we included open-ended questions related to positive and negative aspects of the intervention, and what modifications to the YSLQQ program they suggest.
Feasibility
The feasibility of the recruitment process was measured using a registry of consent response rates and questionnaire response rates. The feasibility of the intervention implementation was measured using a registry of the number of sessions implemented.
Fidelity and quality of the implementation
Fidelity was assessed using a self-report questionnaire answered by each of the facilitators, in addition to a questionnaire answered by an external observer who rated the recording of the sessions performed by the facilitators. These questionnaires included questions related to the program, how much the facilitators implemented the session activities according to the manual, session times, classroom climate, performance, overall evaluation, and the relationship between the facilitator and the students and school teachers.
Secondary outcomes
Substance use and prevention-related skills promoted by the program
The evaluations were carried out during class hours, in a schedule pre-established by the schools; the evaluators answered questions and clarified doubts to the students to answer the instruments. The Eu-Dap questionnaire was administered before (beginning of the academic year) and after the intervention (end of the academic year) at equivalent times for the control and the intervention groups.
European Drug Addiction Prevention Questionnaire (Eu-Dap). This instrument gathers information, knowledge, and opinions about the consumption of substances of abuse, with a main emphasis on alcohol, tobacco, and marijuana. It contains 50 questions, distributed in the following domains: (1) identification (sociodemographic aspects), (2) tobacco use, (3) alcohol use, (4) marijuana use, (5) use of other drugs, (6) information about substances, (7) beliefs about substance use by close relatives, (8) parents' perception of permissiveness in relation to substance use, (9) school performance, includes scales on protective and risk factors for substance abuse: (1) positive and negative beliefs about tobacco use, (2) positive and negative beliefs about alcohol use, (3) positive and negative beliefs about marijuana use, (4) expectations of future use, (5) perception about beliefs about substance abuse use, (6) Perceived risk of substance abuse, (7) normative beliefs about close friends regarding school and substance abuse, (8) normative beliefs about peers regarding substance abuse, (9) parenting styles, (10) family dynamics and parenting styles, (11) school bonding, (12) perception of problems caused by substance abuse, (13) Decision making, (14) peer pressure, (15) self-esteem, (16) response to aggression by others, (17) Assertiveness. The psychometric properties of the validation of this instrument for the Chilean population can be seen elsewhere (36).
Data analysis
For primary outcomes, we described the mean score and standard deviations reported by students regarding the acceptability of several aspects of the intervention described above. Additionally, we extracted qualitative data from the surveys used to assess the acceptability. We organized the information into three categories, following the recommendations by Macklem (37): content, pedagogy, and logistics. We reported the frequencies revealed by the students in each of these categories. Content refers to the knowledge, attitudes, values, norms, and skills addressed by the program and will be the mediators of the behavior change we want to prevent. This component has also been called "adherence", or if the program was delivered or implemented in the way it was designed or written. Pedagogy involves the teaching methods, strategies, and facilitator-student interactions, which contribute to the effectiveness of the program. This component has also been called the "quality of delivery" of the program or the way in which the facilitator implements the program (for example, the facilitator's training, skills in the methods described in the programs, enthusiasm, preparation, attitudes, etc.). The logistic includes "exposure" or "dose" (number of sessions, duration of each session, frequency of sessions, amount of material received, etc.)
For secondary outcomes, firstly, we used descriptive statistics to assess balance across arms at baseline. The primary between-group analysis was carried out on an intention-to-treat basis for post-intervention monthly tobacco, alcohol, drunkenness, and cannabis prevalence and Eu-Dap subscales scores. We used linear mixed-effects model analysis to compare the intervention and control groups regarding the change in secondary outcome measures from baseline to post-intervention. Schools were included as a random factor for each outcome measure to account for possible school effects.