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Clinical efficacy, safety and applicability of home-based bright light therapy in outpatient adolescents with major depressive disorder in China: protocol for a randomised controlled trial

Zhao Z, Zhou T, Liu M, Wang N, Li Y, Yang C, Qiu Y, Wang J et al.

BMJ open, 2026

126 participants

Abstract

Introduction: Major depressive disorder (MDD) is a leading cause of disability among adolescents, yet available treatments remain limited. Bright light therapy (BLT) is a non-pharmacological intervention with demonstrated efficacy in adults. However, its clinical utility and underlying neural mechanisms in adolescents remain unclear. This trial aims to evaluate the clinical efficacy, time to onset, safety and applicability of home-based BLT in outpatient adolescents with MDD, and to explore its underlying neural mechanisms using functional near-infrared spectroscopy (fNIRS).

Methods and analysis: This is a randomised, placebo-controlled, three-arm multicentre clinical trial. A total of 126 outpatient adolescents aged 13-17 years with MDD will be randomly assigned to receive high-intensity BLT, medium-intensity BLT or placebo dim red light using a portable light box in a home-based setting for 40 min each morning over 4 weeks, followed by a 2-week follow-up. 42 age-matched and gender-matched healthy controls will also be enrolled for baseline assessments only, serving as normative references for comparison. The primary outcome will be the change in total scores on the 17-item Hamilton Rating Scale for Depression from baseline to week 4. All analyses will follow an intention-to-treat framework to ensure methodological rigour. The primary outcome will be analysed using analysis of covariance and linear mixed-effects models. Secondary outcomes will include response and remission…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 126 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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