Figure A1.

Concept map children, group 1. In this map, each point reflects one idea. Ideas that were grouped together more often appear closer to each other on the map. Ideas never/rarely grouped together appear widely separated on the map. Clusters are groups of ideas that were grouped together most often and reflect ideas that are conceptually related according to the participants in this group. The defined cluster names in this concept map were: Cluster 1: Screen behaviour; Cluster 2: Noise, distractions and light; Cluster 3: Being unable or reluctant to sleep; Cluster 4: Illness or restless; Cluster 5: Stressful and exciting thoughts and feelings; Cluster 6: Being afraid or uncomfortable in bed. Arrows indicate an idea is reallocated by researchers; idea 10 ‘Watching series in bed and wanting to keep watching’ was reallocated to Cluster 1, and idea 36 ‘Being bullied at school and thinking about the next day when I am in bed’ and 44 ‘Feeling sad’ were reallocated to Cluster 5.