Adolescents treated with antipsychotic medication are at increased risk of developing obesity and related metabolic complications. Interventions that specifically target antipsychotic-associated weight gain in this population are scarce. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have shown efficacy for obesity treatment in adults and adolescents, prompting evaluation of their feasibility and acceptability among young people receiving antipsychotic therapy.
The primary aim of the GOAL trial is to assess feasibility of a 36-week treatment period with a GLP-1 RA as an adjunct to standard care in adolescents with antipsychotic-associated obesity. Feasibility is operationalised as completion from baseline to end of treatment. Findings will inform the design and scaling of a subsequent randomised controlled trial.
The GOAL trial is a single-arm, open-label feasibility study. The study is conducted at Copenhagen University Hospital, Bispebjerg, Denmark, in collaboration with the Child and Adolescent Mental Health Center. Participants will receive the intervention in addition to standard clinical care and will be followed during an 18-month observational period after the 36-week treatment phase.
A total of 34 adolescents aged 12–18 years will be enrolled. Inclusion criteria specified in the protocol include:
The study population includes adolescents with a range of psychiatric diagnoses that require antipsychotic treatment, including psychotic disorders, mood disorders and neurodevelopmental disorders. The protocol excludes adolescents who are receiving antipsychotic treatment under coercion.
Participants will receive once-weekly subcutaneous semaglutide administered for a 36-week treatment period. The dose may be escalated up to 2.4 milligrams weekly, in line with the dosing strategy described in the protocol. Semaglutide is provided in addition to participants’ usual standard care; the protocol does not report additional experimental behavioural or lifestyle interventions beyond usual care.
Following the 36-week active treatment, participants will enter an 18-month observational follow-up to monitor longer-term outcomes and safety signals after treatment cessation.
Primary outcome
Feasibility outcomes
Feasibility outcomes will be analysed descriptively to inform feasibility of progression to a randomised trial.
Secondary and exploratory outcomes
Exploratory longitudinal analyses of secondary outcomes will be conducted using linear mixed-effects models to account for repeated measures over time.
The trial is framed as a feasibility study; accordingly, feasibility outcomes will be reported descriptively. For secondary and exploratory outcomes, the protocol plans longitudinal analyses using linear mixed-effects models to evaluate trajectories over the treatment and follow-up periods. The summary does not provide further details on sample size calculations beyond the target enrolment of 34 participants or detailed statistical parameter specifications; such details are not reported in the source summary.
The study complies with the Declaration of Helsinki and the European Union Clinical Trials Regulation (536/2014). It is approved and registered in the Clinical Trials Information System with the registration number 2024-5 17 471-21-02. Written informed consent will be obtained from participants and their legal guardians prior to enrolment.
Results from the GOAL trial will be disseminated through peer-reviewed publications and presentations at scientific conferences. The feasibility outcomes and secondary analyses will guide the design and scaling of a future randomised controlled trial testing GLP-1 RA therapy in adolescents receiving antipsychotic medication.