Randomized controlled trial of Group Interpersonal Therapy conducted by non-specialists versus waiting list for symptoms of depression and anxiety in community young adults: a Research protocol

Introduction Depression is a highly prevalent and potentially chronic mental disorder with significant impact on quality of life and social support, with a frequent onset in early adulthood. Despite the existence of effective treatments, many individuals do not have access to care, do not respond to, or do not tolerate medications. Additionally, access to mental health services remains limited, especially in low- and middle-income countries, where the World Health Organization estimates that 75% of individuals do not receive adequate care. Group Interpersonal Therapy (IPT-G) is an evidence-based, structured psychotherapy recommended by international guidelines for the treatment of depression and is adaptable for task-shifting approaches in primary care. Previous research has shown promising results for IPT-G delivered by non-specialists in low-resource settings in an open study, but randomized trials by non-specialists are still lacking. Objectives To evaluate the improvement in depressive symptoms after eight sessions of IPT-G among young adults with depressive symptoms in a community setting, conducted by non-specialists in a randomized trial, representing a new step in demonstrating scientific evidence for novel clinical treatments. Methods This randomized controlled clinical trial is planned to include 80 participants randomized (1:1) between an interventional (IPT-G) and a control (waiting list) group. Our study will enroll young adults aged 18 to 24 years with depressive symptoms. The intervention will focus on interpersonal relationships within the IPT model and will be delivered by a university student and a medical doctor trained in IPT. The primary outcomes are depressive symptoms; secondary outcomes include quality of life and social support. Results The trial was approved by the Research Ethics Committee (CEP) of the HCPA (Project number: 2023-0283, CAAE: 73830223.7.0000.5327) and registered on ClinicalTrials.gov ( NCT06480019 ). Recruitment started in February 2024 and is ongoing. Conclusion This study could support the integration of IPT-G delivered by non-specialists into public health systems worldwide as a low-cost and accessible intervention. Findings could help reduce mental health service gaps and increase the capacity of public health systems to treat depression. STRENGTHS AND LIMITATIONS OF THIS STUDY This study has the strength of being the first randomized controlled trial evaluating IPT-G delivered by non-specialists. It is conducted in a middle-income country, where, despite the existence of guidelines recommending IPT-G implementation by non-specialists, there are no randomized trials. The study also has some limitations: participants are not restricted from seeking other mental health treatments during the trial, and the intervention is compared with a waitlist control rather than an active treatment condition. Version 2.0 – 10 October 2025 (Final version submitted)