Trans young people are at a higher risk of mental health difficulties such as depression, anxiety and suicidality than their cisgender peers, due in part to their experiences of minority stress. This protocol describes a feasibility trial and subsequent pilot randomised controlled trial (RCT) of a codesigned group cognitive–behavioural therapy intervention for trans young people, named Trans Adolescent Group ThErapy for Alleviating Minority stress (TAG TEAM).

To evaluate TAG TEAM, we will conduct a feasibility trial followed by a pilot RCT with trans young people aged 14–16 years who have been referred to the Royal Children’s Hospital Gender Service in Melbourne, Australia. In the feasibility trial, we aim to enrol 32 participants who will be randomised at a 1:1 ratio to either in-person or online intervention arms. Participants will be assessed at baseline and post-treatment, with a nested qualitative evaluation post-treatment. Primary outcomes are the feasibility and acceptability of the intervention and the study design and associated procedures, including comparison of the in-person and online delivery modes. In the subsequent pilot RCT, we aim to enrol 64 participants who will be randomised at a 1:1 ratio to an intervention or waitlist control arm, with delivery mode determined by the feasibility trial. Participants will complete assessments at baseline, post-treatment and 3-month follow-up. Primary outcomes are the feasibility and acceptability of the RCT study design. In both the feasibility trial and pilot RCT, participants will complete assessments related to mood, anxiety, suicidality, quality of life, minority stress, family support and social transition. Quantitative data will be analysed using descriptive statistics. Qualitative data will be analysed using thematic and interpretive analysis.

The Royal Children’s Hospital Human Research Ethics Committee has approved this study (#91162). Informed consent will be obtained in writing from all participants and a legal guardian. Findings will inform the development of a full-scale RCT to evaluate the efficacy of TAG TEAM and will be disseminated through conferences and peer-reviewed journals.

ACTRN12623000302651, ACTRN12623000318684.