Prevention of Anxiety and Depression in Swedish School Children: a Cluster-Randomized Effectiveness Study.

Our study aimed at evaluating FRIENDS for Life, an intervention to prevent anxiety and depression in Swedish school children. A total of 695 children between the ages of 8 and 11 were recruited from 17 schools in Stockholm, Sweden, and cluster-randomized to either the intervention or control group. Teachers in the intervention group received a full day of training and administered FRIENDS for Life in their classrooms. We assessed the children's anxiety and depressive symptoms, general mental health, and academic performance at pre- and post-intervention as well as at the 12-month follow-up. A multi-informant approach was used with data collected from children, parents, and teachers. Assessment was done with the Spence Children's Anxiety Scale, Children's Depression Inventory, and the Strengths and Difficulties Questionnaire. Children's baseline symptoms, gender, and age as well as their teacher's use of supervision were examined as moderators of effect. Our study found no short- or long-term effects of the intervention for any outcome with regard to the entire sample. We found an enhanced effect of the intervention regarding children with elevated depressive symptoms at baseline. We found a decrease in anxiety symptoms among children whose teachers attended a larger number of supervision sessions, compared to children whose teachers attended fewer supervised sessions or the control group. Mediation analyses showed that this effect was driven by change in the last phase of the intervention, suggesting that supervision might play an important role in enhancing teachers' ability to administer the intervention effectively.