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.

Background: The landscape of mental health treatment is expected to change due to the widespread use and availability of the Internet and mobile devices, as well as their increased capacity to deliver quality interventions. The development of treatment apps, such as the one investigated in the proposed study, will help to dismantle some of the barriers that prohibit youth from seeking or accessing treatment under the current health care model.

Smartphone interventions are particularly promising due to their ability to provide treatment exercises and monitor symptoms in situ (i.e., in real-time), immediately after or before pivotal events. A recent systematic review pointed out that some studies utilizing these digital interventions have high attrition rates; in some cases, rising as high as 70%. This is likely due to the fact that youth do not enjoy using digital health care systems that they perceive as impersonal and confusing to navigate.

Objective: Thus, the present study aims to determine which mobile-sensed daily life behaviours are indicative of anxiety problems by comparing the mobile- sensing profiles of youth with and without anxiety disorders as well as to evaluate the effectiveness of the novel treatment app on youth with anxiety disorders. The SMILE app incorporates Cognitive Behavioral Therapy (CBT) based treatment functions to help patients improve their mental health.

Method: Participants will be recruited and randomly allocated into the intervention and the control group. The study will measure anxiety, depression, drug and alcohol problems, and sleep problems before and after the one-month intervention period as psychological variables. Additionally, a 3-month follow-up will be the defining response of success for the SMILE app as participants will be asked to rate the app's ease of use, helpfulness, understandability, and if they would recommend the app to a friend.

Implications: If the intervention demonstrates effectiveness in reducing anxiety symptoms, it will undergo further testing to confirm its reliability and generalizability across diverse youth populations. Following these evaluations, the intervention will be integrated into the clinical care of youth with anxiety disorders, serving as both a stand-alone treatment option and a supplemental tool to complement existing therapeutic approaches, such as cognitive-behavioral therapy (CBT). This dual application will enable its use in various care settings, enhancing accessibility and providing tailored support to address the unique needs of individuals. Ultimately, the intervention aims to improve treatment outcomes, empower youth in managing their anxiety, and reduce the overall burden of anxiety disorders on mental health services.

The study will examine if a significant reduction of anxiety symptoms can be achieved in youth using the novel treatment app. We intend to recruit 120 participants with anxiety disorders between the ages of 12 and 21.

It is hypothesized that:

1. Youth with anxiety disorders will have fewer social interactions, be less physically active/mobile, and sleep worse, indicating areas in which these youth experience problems that the novel treatment app will need to focus on addressing using its features.
2. The effects of the novel treatment app will reduce youths' anxiety problems as measured by the SCARED survey compared to those in the control group.

Inclusion Criteria:

• Ability to read, write, and speak English
• Aged 12-21
• Regular access to and usage of a smartphone
• Score >25 on SCARED (25) (i.e., youth with anxiety disorders)

Exclusion Criteria:

• Other psychotherapy-based intervention
• Major medical illnesses which might impact participation (e.g., long periods of hospitalization)
• Youth who cannot provide informed consent (as this is a self-directed treatment program).

Participant data will be made available upon reasonable request to Dr. Sandra Meier (PI).