A Freely Accessible, Anonymous Online Treatment for Social Anxiety: Protocol for a Partially Randomized Patient Preference Trial.

Background Many people with mental health problems do not receive the care they need. Digital mental health interventions have been shown to be effective in many trials and offer a promising way to reach more people in need. However, their uptake and use remain limited, in part due to concerns about data privacy. However, these concerns may not be equally significant for all users.Objective This trial aims to evaluate the efficacy of an anonymous online self-help tool for social anxiety that processes no personal data and has some disadvantages in terms of usability compared to an otherwise identical, nonanonymous evidence-based tool. Furthermore, the trial will investigate user preferences regarding the 2 program versions and evaluate the impact of these preferences on treatment outcomes.Methods In this partially randomized patient preference trial, 2 versions (anonymous vs nonanonymous) of the same previously researched program will be compared among 452 participants with increased levels of social anxiety. Half of the participants will be randomized to one of the program versions, whereas the other half will be assigned to their preferred version. The primary outcome is social anxiety symptoms. Secondary outcomes include depression, stigma of mental illness, and quality of life.Results Recruitment started in September 2024. As of the date of manuscript submission in May 2025, over 350 participants have been included in the study. Recruitment ended in September 2025, and results are expected to be available and published in 2026.Conclusions The results of this trial will determine whether anonymously accessible interventions, which could easily be made freely available, are less efficacious than their nonanonymous counterparts and will explore the impact of user preferences on treatment outcomes. The findings could contribute to making digital interventions more accessible and tailoring interventions to individual preferences.Trial Registration ClinicalTrials.gov NCT06465589; https://clinicaltrials.gov/study/NCT06465589.International Registered Report Identifier (irrid) DERR1-10.2196/77573.