Can adolescent emotion regulation be improved with an app-based training?

INTERVENTION: Training procedure and timeline The study will have two training arms. An active Affective Control Training (AC‐Training) and a placebo training (P‐Training). The training will be administered via an app. Included participants will be randomized to either the AC‐Training or the P‐Training groups. Both training groups train for 14 days over a four‐week period. They are asked to complete at least 10 minutes of training per day. The total duration of a session is There is no upper limit to the duration of the daily training session. Affective training In the affective training participants train on three different working memory tasks including neutral and affective stimuli (faces and words). The tasks are a visuospatial, auditory and dual n‐back task. They require participants to maintain and update the location of faces, words, or both in working memory. Placebo training The placebo training task requires participants to indicate whether two panels display exactly the same stimuli in the same positions on a grid. As with the affective control training there are three versions: a shapes version including geometric shapes as stimuli, and the other two versions include the same faces and words as the affective control training task. Randomization Condition allocation will be concealed to experimental staff by using computer‐generated condition assignment stratified by age (young adolescents, 11‐14 years, and mid‐late adolescents, 15‐19 years). Allocation will be based on a blocked randomization sequence with randomly mixed block sizes (2‐6), which prevents the experimenter from deducing any potential sequencing even with awareness of the randomization type. To investigate this hypothesis, we will compare individuals’ performances on the affective n‐back task, which is a slightly modified (i.e., including different stimuli and fewer trials) CONDITION: Adolescent mental health and emotion regulation ; Mental and Behavioural Disorders ; N/A PRIMARY OUTCOME: ; 1. Mental health will be measured using the strengths and difficulties questionnaire before training, immediately after training, one month after training and one year after training.; 2. Affective control will be measured using computerized assessments of affective inhibition, updating and shifting before training, immediately after training, one month after training and one year after training.; 3. Emotion regulation will be measured with the Difficulties in Emotion Regulation Scale will be assessed before training, immediately after training, one month after training and one year after training.; SECONDARY OUTCOME: 1. Self‐regulation will be assessed with the Brief version of the Self‐control Scale before training, immediately after training, one month after training and one year after training. 1.1. It will also be assessed by deriving a ratio of the time spent on the most demanding versus less demanding training tasks. INCLUSION CRITERIA: 1. Aged between 11‐19 years old 2. Speak English fluently