Effect of Motivational Interviewing on depression scale scores of adolescents with obesity and overweight

The aim of this study was to compare the effect of motivational interview (MI) with conventional care on the depression scale scores of adolescents with obesity/overweight. It was a controlled cluster randomized trial with parallel design, including two groups: intervention group [Motivational Interview Group (MIG)], control group [Conventional Intervention Group (CIG)]. Intervention: three face-to-face 30 min' interviews three months apart (only MIG interviews were based on MI principles). Outcomes: change in Children Depression Inventory (CDI) scores. We used a mixed repeated-measures ANOVAs analysis to assess the group vs time interaction. Effect size was calculated for ANOVA with difference of means of the total score (DOMTS). CDI scores were compared by a paired t-test. Eighty-three (84%) adolescents finished the intervention. There was a significant time vs group interaction both groups. While in the CIG scores significantly increased, in the MIG the scores significantly decreased. The DOMTS was significantly different between the two groups. We concluded that MI showed a positive effect on depression scale scores over time relatively to conventional intervention.