Time-based changes in factor scores by group.

Improving mental health literacy in adolescents is a global priority. The purpose of this study is to examine differences in students’ attitudes across five components of mental health literacy—supportability, severity, susceptibility, recoverability, and preventability—by comparing classes led by individuals with lived experience of mental illness and textbook-based classes led by teachers. This study focuses on high school students in Japan, where educational interventions in mental health literacy remain limited. This quasi-experimental study examined changes in mental health literacy among 150 Japanese high school students (aged ≥15) following two types of instruction: one for students who received lessons from individuals with lived experience of mental illness (lecturer-guided), and another by a teacher using textbook content (non-lecturer-guided). A 24-item questionnaire measuring five mental health literacy components—supportability, severity, susceptibility, recoverability, and preventability—was administered at three time points: pre-, post-, and 3-month follow-up. Valid responses from 117 students were analyzed using factor analysis and ANOVA. Five factors were extracted with acceptable internal consistency. The lecturer-guided group showed significant post-intervention improvements in severity, susceptibility, and recoverability (p