This clinical trial aims to evaluate the effectiveness and underlying processes of change of the Unified Protocol (UP) for treating emotional disorders in a university outpatient clinic. The study will involve 140 patients receiving UP treatment in a group format, delivered either by experienced or novice therapists, along with a non-clinical control group of 45 participants. Participants will self-refer on the basis of advertisement about the study through flyers, posters, project website, social media or local news media. Outcomes will be assessed through self-report measures of well-being, symptoms, emotion regulation, and the non-specific factors of treatment credibility and therapeutic alliance. Additionally, psychophysiological measures of heart rate variability and interoception will be used to explore processes influencing treatment response. Qualitative interviews will complement the quantitative data by capturing participants' perspectives on the treatment and experiences of what contributed to change.