An App Responding to Behaviour of People to Promote Mental Wellbeing in Anxious Youth

The goal of this clinical trial is to utilize mobile-sensing techniques to produce and test a simplified and personalized treatment app, Smile for Life (SMILE), for youth diagnosed with an anxiety disorder. The main questions it aims to answer are: 1. What specific areas of difficulty (e.g., social interactions, physical activity/mobility, and sleep quality) are most impacted in youth with anxiety disorders, and how can a novel treatment app address these challenges? 2. Does the use of the novel treatment app lead to a measurable reduction in anxiety symptoms among youth, as assessed by the Screen for Child Anxiety Related Disorders (SCARED) survey, compared to a control group? Researchers will compare the intervention to a control group (a group not given the SMILE app) to see if the intervention works to improve psychological functioning. Participants will: * Complete an online survey on emotional well-being and personality traits at the beginning and end of the one-month study, as well as at the 3-month follow-up. Participants will receive daily notifications asking participants to rate their social-emotional functioning. The app will then recommend a treatment plan and also ask participants to rate how helpful treatments were. Three months after the end of the study, participants will be asked to complete a follow-up assessment rating the app's usability. * Participants in the intervention group will use a mobile app to practice cognitive behavioural therapy (CBT) treatment for their social-emotional issues.