Retraining automatic attention and approach tendencies to reduce levels of problematic cannabis and alcohol use for youth in juvenile detention centers.

This study aims to assess the effectiveness of Cognitive Bias Modification (CBM) on top of care-as-usual in reducing levels of problematic cannabis and alcohol use. We focus specifically on youth placed in juvenile detention centres in the Netherlands, as this is a demographic that shows high levels of problematic substance use compared to their general population peers. The CBM training consists of two computerized tasks, either one of which is randomized to be either an active training or a placebo version. In this way we ensure that 75% of our participants receive at least one active training task while retaining a control group.

-We expect that the youth who receive an active CBM training on top of care-as-usual show a greater reduction in cannabis or alcohol misuse at follow up when compared their general population peers.

-We expect that CBM training works by reducing attention and approach bias towards the substance in question.

-We will explore whether the actively trained participants also show less delinquent behaviour when compared with the participants who received a placebo training.

- T0 (screening & substance use baseline): At least 2 weeks after placement in the institution.

- T1 (cognitive biases baseline): As soon as screening results have shown them to be eligible and voluntary consent has been obtained.

- T2-T6 (training sessions): At least 24 hourse between sessions and preferably no more than a week apart.

- T7 (1st follow-up): 1 month after the last training session.

- T8 (2nd follow-up): 3 months after the last training session.

- T9 (3rd follow-up): 12 months after the last training session.

5 sessions of CBM comprised of two computerized tasks, an Approach-Avoid task to target approach biases and a Visual Probe task to target attention biases. CBM is done in addition to care-as-usual. Participants receive either an active training version or a placebo version of either task.