{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:42:02Z","timestamp":1782488522176,"version":"3.54.5"},"reference-count":32,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,20]],"date-time":"2023-01-20T00:00:00Z","timestamp":1674172800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003107","name":"Federal Ministry of Health","doi-asserted-by":"publisher","award":["ZMVI1-2519DSM216"],"award-info":[{"award-number":["ZMVI1-2519DSM216"]}],"id":[{"id":"10.13039\/501100003107","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Vocational students are a risk group for problematic substance use and addictive behaviors. The study aim was to evaluate the effects of an app-based intervention on tobacco, e-cigarettes, alcohol, and cannabis use as well as gambling and digital media-related behaviors in the vocational school setting. A total of 277 classes with 4591 students (mean age 19.2 years) were consecutively recruited and randomized into an intervention (IG) or waitlist control group (CG). Students from IG classes received access to an app, which encouraged a voluntary commitment to reduce or completely abstain from the use of a specific substance, gambling, or media-related habit for 2 weeks. Substance use, gambling, and digital media use were assessed before and after the intervention in both groups with a mean of 7.7 weeks between assessments. Multi-level logistic regression models were used to test group differences. Intention-to-treat-results indicated that students from IG classes had a significantly larger improvement on a general adverse health behavior measure compared to CG (OR = 1.24, p = 0.010). This difference was mainly due to a significantly higher reduction of students\u2019 social media use in the IG (OR = 1.31, p &lt; 0.001). Results indicate that the app \u201cMeine Zeit ohne\u201d is feasible for the target group and seems to have a small but measurable impact on students\u2019 health behavior.<\/jats:p>","DOI":"10.3390\/ijerph20031970","type":"journal-article","created":{"date-parts":[[2023,1,23]],"date-time":"2023-01-23T02:01:02Z","timestamp":1674439262000},"page":"1970","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Effects of an App-Based Intervention Program to Reduce Substance Use, Gambling, and Digital Media Use in Adolescents and Young Adults: A Multicenter, Cluster-Randomized Controlled Trial in Vocational Schools in Germany"],"prefix":"10.3390","volume":"20","author":[{"given":"Benjamin","family":"Pietsch","sequence":"first","affiliation":[{"name":"IFT-Nord Institute for Therapy and Health Research, 24114 Kiel, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicolas","family":"Arnaud","sequence":"additional","affiliation":[{"name":"German Centre for Addiction Research in Childhood and Adolescence, University Medical Centre, Hamburg-Eppendorf, 20251 Hamburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kirsten","family":"Lochb\u00fchler","sequence":"additional","affiliation":[{"name":"IFT Institut f\u00fcr Therapieforschung, 80804 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Rossa","sequence":"additional","affiliation":[{"name":"IFT Institut f\u00fcr Therapieforschung, 80804 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ludwig","family":"Kraus","sequence":"additional","affiliation":[{"name":"IFT Institut f\u00fcr Therapieforschung, 80804 Munich, Germany"},{"name":"Department of Public Health Sciences, Centre for Social Research on Alcohol and Drugs, Stockholm University, 11419 Stockholm, Sweden"},{"name":"Institute of Psychology, ELTE E\u00f6tv\u00f6s Lor\u00e1nd University, 1053 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elena","family":"Gomes de Matos","sequence":"additional","affiliation":[{"name":"IFT Institut f\u00fcr Therapieforschung, 80804 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristin","family":"Grahlher","sequence":"additional","affiliation":[{"name":"German Centre for Addiction Research in Childhood and Adolescence, University Medical Centre, Hamburg-Eppendorf, 20251 Hamburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rainer","family":"Thomasius","sequence":"additional","affiliation":[{"name":"German Centre for Addiction Research in Childhood and Adolescence, University Medical Centre, Hamburg-Eppendorf, 20251 Hamburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7163-5738","authenticated-orcid":false,"given":"Reiner","family":"Hanewinkel","sequence":"additional","affiliation":[{"name":"IFT-Nord Institute for Therapy and Health Research, 24114 Kiel, Germany"},{"name":"Institute for Medical Psychology and Medical Sociology, University Medical Center Schleswig-Holstein (UKSH), 24105 Kiel, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthis","family":"Morgenstern","sequence":"additional","affiliation":[{"name":"IFT-Nord Institute for Therapy and Health Research, 24114 Kiel, Germany"},{"name":"Institute for Medical Psychology and Medical Sociology, University Medical Center Schleswig-Holstein (UKSH), 24105 Kiel, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Bannink, R., Broeren, S., Heydelberg, J., van\u2019t Klooster, E., and Raat, H. 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