BackgroundReferrals for child and adolescent acute psychiatric treatment have spiked in the last two years. To provide these adolescents with a fast-acting intervention, a novel treatment approach for acute emotional dysregulation was evaluated in this study.Methods156 adolescents between the age of 13 and 18 years who were admitted to a psychiatric unit for acute emotional or behavioral dysregulation participated in a 5-week-group program (Stress-Arousal- Regulation-Treatment, START) which consisted of two sessions per week (60 min/session). Pre- and post intervention psychometric measures were derived for each participant applying the Self-Control Scale (SCS-13), the FEEL-KJ capturing adaptive and maladaptive emotion regulation strategies, the Perceived Stress Scale (PSS-10), as well as the Strengths and Difficulties Questionnaire (SDQ).ResultsThe mean score of maladaptive emotion regulation strategies of the FEEL-KJ significantly decreased post treatment (d = −0.24, p = .001), while there was an increase in adaptive emotion regulation strategies (d = 0.25, p = .001). The post- intervention-assessment revealed significantly lower scores in the PSS-10 (d = −0.34, p < 0.001), as well as SDQ mental health problems (d = −0.17, p = .018) and disorders (d = −0.15, p = .015). The Self-Control Score increased significantly after the intervention (d = 0.21, p = .001).ConclusionsIn this large sample, the low-threshold intervention START significantly improved emotion regulation and self-control and reduced perceived stress as well as several scales of the strengths and difficulties questionnaire, pointing to a good feasibility and indicating efficiency to provide support to adolescents with acute mental health problems when applying this short-term treatment.