Background: Meta-analyses from school studies point to better effects from studies lasting a whole school year compared to shorter studies . Traditional forms of evaluation like questionnaires can pose a challenge for children in reliably describing psychological changes over a period of time.
Aim: To enhance child wellbeing through an extensive positive psychology intervention.
Method: A whole school year project aimed at students in middle school (11-12 year olds, N=154) with a clustered RCT design. All participants were evaluated before and after the intervention with an extensive set of measures including a web-based questionnaire, experience sampling of daily life as well as with physiological measures (heart rate variability and salivary samples of cortisol) and focus groups interviews. A shorter follow-up was performed 5 months after the intervention.
Results: Children in the intervention group showed significantly higher levels of overall wellbeing, positive emotions and hope. Correspondingly, negative daily emotions diminished significantly. In addition, there were selective significant effects on depressive symptoms and behavior problems. Physiological measurements revealed significant effects on stress levels among groups. Results were maintained at follow-up.
Conclusions: The intervention showed significant effects on wellbeing among middle school students as measured through a broad array of measurements.