We evaluated the extent to which receiving the school-based multi-component treatment of the Challenging Horizons Program (CHP) would lead to significant improvements in levels of symptoms of attention deficit hyperactivity disorder (ADHD) and social and academic functioning for high school aged adolescents diagnosed with ADHD. We intended to recruit 200 high school aged adolescents with a diagnosis of ADHD who would be randomly assigned to either CHP or a Community Care condition within each of 12 participating high schools. Outcome measures included parent, teacher and adolescent reports as well as observational data. Measures were collected at initial evaluations which preceded the one academic year of treatment, during the treatment period, and at six-months after treatment ended. Based on previous research with this treatment in middle and high schools, we anticipated meaningful gains for those in the treatment condition at post-treatment and larger gains on some variables at the 6-month follow-up evaluation. Eligible participants were stratified for medication status and sex following the completion of all eligibility assessments for each of 3 cohorts and were randomly assigned (within schools) to either the CHP or CC condition. Siblings were assigned together such that they would be in the same condition. All measures (except the achievement test which was given at eligibility and post-treatment assessment points) were administered on at least three occasions including pre-treatment (i.e., eligibility or baseline), post-treatment, and 6-month follow-up. Rating scales were completed online using REDCap (Harris et al., 2009) with the exception of the School Functioning Scale.

Participants randomized to the treatment group met with their coaches individually for approximately 15-20 minutes twice per week throughout the academic year, typically during lunch, study hall, or an elective class. Individual sessions included study skills, organization, problem solving, and interpersonal skills training. Ten, 90-minute group sessions were offered to adolescents and parents in the evenings and ran concurrently. The organization intervention occurred during each individual session. During initial sessions, students and coaches worked collaboratively to develop a system of organizing the student's binders or folders and tracking assignments in a daily planner or electronic calendar. Subsequent sessions included a binder and daily planner check in which the student's adherence to the system was recorded and then the student practiced addressing disorganization (e.g., put assignments in the correct folders, update planner). After meeting objective criteria for organization (e.g., at least 80% planner completion for two consecutive weeks), adolescents independently completed organization and planner checks under supervision by coaches.

Each month, coaches checked with students and school records regarding six areas of risk including tardiness, absenteeism, in-school disciplinary actions, out-of-school suspension, failing classes, and missing assignments. If students met a predetermined threshold for risk (e.g., 80% or fewer assignments turned in on time), then the student and coach had a problem-solving discussion. The goal was to both develop a solution to the relevant problem as well as teach students how to use problem-solving skills. The process included (1) defining the problem, (2) setting a goal, (3) brainstorming ways to achieve that goal, (4) selecting one or more of these solutions, (5) determining how to know if the plan is working, (6) setting a date to start implementation, and (7) setting a date to review the success of the plan. During a subsequent session, the coach and student reviewed the results of the plan relative to stated goals and determined if they should continue the plan or make changes. During individual sessions, students and coaches critically reviewed social events and the student's behavior in relation to goals. This was an extension of the evening sessions focused on ISG and involved applying the skills learned in the group meetings to individual social events in the participants' daily lives. For students who were not performing well on tests and quizzes, coaches provided study skills intervention. Coaches reviewed test-taking strategies regarding different styles of test questions (e.g., planning an outline for an essay question). Students were tested on these strategies to demonstrate mastery and then practice the skills on practice tests. Students also learned strategies for using flashcards and class notes effectively to prepare for tests. In the ten evening sessions offered for students the adolescents participated in an interpersonal skills group (ISG) to improve social skills. During the first group, students were introduced to the concepts of ideal self - how they want to be seen, and real self - how they really are seen. Students developed ideal self goals and practiced behaving in ways that aligned with these goals during games and activities and frequently reviewed progess with staff. Parents were offered 10 evening sessions concurrent with students' ISG. Program staff provided psychoeducation about ADHD and common difficulties faced by teenagers, including sleep hygiene. Parents also worked with project staff to develop a homework management plan that determined when students would complete homework each night and for how long.

Participants who were randomized to the CC condition were given a list of available resources in their community and received no services from research staff. Participants in both CC and the treatment condition were informed that they could receive any community services during the duration of the trial.