Accessible mental well-being intervention for adolescents in school settings: a single-group intervention study using a pretest–post-test design

BACKGROUND: A growing number of adolescents seek treatment for mental health problems, a circumstance that stresses the importance of implementing accessible treatment options. This study evaluates the impacts of brief, mental well-being intervention for adolescents in a school environment. As mental health interventions are often targeted at specific disorders, we sought a comprehensive approach to reach adolescents with a range of mental health symptoms. METHODS: Single-group intervention study with a pretest–posttest design was utilized and conducted in lower, upper secondary, and vocational schools on adolescents ages 12–18 who sought medical attention for mental health symptoms. The cut-off point for inclusion was ≥ 14, for the Young Persons Clinical Outcomes for routine Evaluation (YP-CORE) measurement. The intervention included six face-to-face visits implemented by psychiatric nurses who received a 3-day training course. The impacts were evaluated after 6 weeks (n = 87) and again at 6 months (n = 68) and assessed using the YP-CORE, Beck Depression Inventory (BDI-II) and Overall Anxiety Severity and Impairment Scale (OASIS). RESULTS: The participants reported significant levels of mental distress at baseline with a YP-CORE mean score = 21.48, a BDI-II mean score = 23.60, OASIS mean score = 10.98. Post-intervention results at 6 weeks for the primary outcome YP-CORE showed a significant (p < .001) mean score decrease of − 3.82, a medium effect size d = .627. For participants attending upper secondary and vocational schools the YP-CORE scores changed significantly from baseline to 6-weeks (p = .005) and from baseline to 6-months (p < .001). Long-term outcomes at 6-months showed a − 1.14 decrease (p = non-significant), effect size d = .175. After the 6-week intervention, 12% of the participants were assessed as not requiring additional visits. CONCLUSIONS: This easily accessible intervention in a school setting indicated improvement for those participants with mild to moderate mental disorder symptoms and attending upper secondary and vocational schools. After the 6-week intervention, significant positive effects were observed. Participants reported substantial levels of mental distress at the baseline, which could contribute to the decline of symptoms and need for extended care during the 6 months follow-up. Trial registration Retrospectively registered with Clinicaltrials.gov identifier NCT05356949 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13034-023-00576-0.