Girls-only vs. mixed-gender groups in the delivery of a universal wellness programme among adolescents: A cluster-randomized controlled trial

Investigation of the optimal setting for body image prevention programmes is important to maximize the outcomes of such programmes. We examined the preferred setting for a school-based wellness programme called "In Favour of Myself". A total of 259 girls (mean 13.82±0.64 years) were divided into a girls-only intervention group, a mixed-gender intervention and a waiting list control group. The participants completed self-report questionnaires at baseline, post-intervention (2 months) and at follow-up (3 months) examining changes in self-esteem, media literacy, body image and risk factors for eating disorders. The intervention group participants also completed a satisfaction questionnaire. Both intervention groups demonstrated statistically significant improvements in identifying advertising strategies (p