Piloting a more intensive 8-week mindfulness programme in early- and mid-adolescent school students.

Aim: It is unclear how adult mindfulness-based interventions (MBIs) should be modified for youth, and at what ages programmes should be implemented for optimal impact. Recent non-replication with a 9-week programme in early adolescence suggested abbreviated programme content might be insufficient and/or that this age group are less receptive. Method: This controlled quasi-experimental design tested a more intensive 8-week MBI (longer meditation and session duration, plus inquiry) in Year 8 (M _age = 13.47; SD = 0.35) and Year 10 (M _age = 15.47; SD = 0.40) secondary students for feasibility and acceptability (N = 143, 45.9% female). Results: Within this format students rated the content as agreeable, and school staff deemed content developmentally appropriate, across both age bands. Efficacy was tested in a small subsample (N = 90) to provide an estimate of effect size. Linear mixed modelling demonstrated significant between-group differences in depression (Cohen's d = 0.61; 95% CI = 0.19 to 1.03) and anxiety (d = 0.52; 95% CI = 0.10 to 0.94) at 4-month follow-up, but not immediately post-intervention. Conclusion: An MBI more closely modelled on adult curricula was acceptable to students, although session duration was harder to timetable by schools. Promising effect sizes support further investigation in a larger sample.