Feasibility and Efficacy of Imager, a Digital Training Intervention to Increase Reward Sensitivity: A Randomised Controlled Trial

Aim of the current project is to develop and test Ecological Momentary Intervention (EMI) - Imager, to promote and improve stress resilience, specifically to increase reward sensitivity. EMIs are mostly smartphone-based applications that deliver interventions to people as they go about in their daily lives. The EMI developed and tested here is based on theoretical and empirical findings and consists of several items and a repeated training using various individual scenarios from participants' life that will be presented to participants via an app on their smartphones.

This study tests the feasibility and effects of the EMI on a change in (i) reward sensitivity, (ii) mental imagery, and (iii) indices of perceived stress. One hundred twenty healthy student participants, aged 18-29 will be included in the study. Participants will be screened first and included if they score 5 points or more on the Reward Sensitivity Subscale of Behavioral Avoidance/Inhibition (BIS/BAS) scales. This is necessary in order to avoid a ceiling effect. Then, participants will be randomly assigned to an experimental (reward sensitivity EMI) or two of the control conditions (control EMA or waitlist). The reward sensitivity EMI group will be taught about experiencing rewards in daily life and will be asked to apply the specific techniques to personal situations repeatedly. The control EMA group will use the same app consisting of Ecological Momentary Assessment only, and the waitlist group will not receive any mobile app.

The training will last seven consecutive days and the app will send (i) 10 prompts per day to ask about the current mood of the user in control EMA and experimental groups and (ii) three prompts per day resulting in a total of 21 reward training sessions only in the experimental group. Participants will be able to use a special button triggering the intervention or EMA by themselves too. After one week, participants will return to the lab, fill in questionnaires and participate in behavioral tasks.