Not enough of the screened participants met the inclusion criteria. Despite extensive recruitment efforts we could not recruit enough participants to reach the calculated target sample of 86 for randomization.

This study aims to examine the efficacy of exposure using virtual reality (VR) for public speaking anxiety in young adults in two treatment arms: a one-session VR exposure therapy with a 4-week online transition intervention versus a three-session VR exposure therapy with a 4-week online transition intervention. Previous studies have demonstrated that one-session therapy (OST) is comparable to prolonged exposure-based therapies in terms of effectively reducing public speaking anxiety. Moreover, VR offers many benefits compared to in-person exposure, namely the ability to produce anxiety-evoking stimuli without having to leave the therapist's room. However, OST VR exposure has not been directly compared to prolonged VR exposure and not for public speaking anxiety.

Inclusion Criteria:

• aged 18-30 and pursuing higher education;
• experiencing a significant level of public speaking anxiety (60+ on PSAS);
• able to use a computer and have access to the internet for the duration of the study;
• able to understand, write and speak in Lithuanian;
• available to participate in one or three in-person intervention sessions and can devote the time to participate in a 4-week online program following the intervention sessions.

Exclusion Criteria:

• a history of seizures or a history of epilepsy;
• other significant medical conditions that would prevent them from participating in the program;
• high levels of depression (Patient Health Questionnaire-9 rating of 15 and above and mentions of suicidal ideation) or other significant psychiatric conditions that would interfere with participation in the program;
• a tendency to have extreme seasickness reactions or a history of adverse physical reactions to virtual reality experiences or difficulty with or lack of stereoscopic vision;
• current involvement in other psychological interventions such as psychological counseling or psychotherapy;
• use of psychoactive drugs, unless stable for three months;
• current participation in other programs aimed at reducing public speaking anxiety.

Following the publication of trial results, participant-level data without identifying information, i.e., anonymized, will be stored on a national data archive MIDAS and will be made available to researchers affiliated with research institutions upon a reasonable request. Statistical analysis procedures will be clearly defined in papers on trial results.

Following the publication of the trial results.

Available to researchers affiliated with research institutions upon a reasonable request.