# Efficacy of a video‐viewing intervention of smartphone‐based positive word stimulation on depressive symptoms in individuals with subthreshold depression: Protocol for a randomized controlled trial

## TL;DR

This study tests a smartphone-based video intervention to reduce depressive symptoms in people with subthreshold depression.

## Contribution

The study introduces and evaluates a novel smartphone-based video intervention for subthreshold depression.

## Key findings

- The trial will assess the efficacy of SPSRS on depressive symptoms using a randomized controlled design.
- Results will determine if the SPSRS intervention leads to significant improvements in psychological distress and anxiety.
- The study will provide evidence for a new, accessible intervention strategy for subthreshold depression.

## Abstract

Interventions targeting subthreshold depression (StD) are critically important for preventing major depressive disorder's onset. Our smartphone‐based, video‐viewing website (SPSRS), which presents positive word stimulation in videos, is a novel intervention for improving StD's depressive symptoms. Because no rigorous evidence exists for SPSRS's efficacy, this trial aims to evaluate the SPSRS intervention's efficacy on depressive symptoms.

The trial will be an evaluator‐blinded, randomized, 5‐week, parallel‐group superiority trial designed to assess whether the SPSRS intervention (experimental group) is effective compared to no intervention (waiting‐list control group). In a 1:1 ratio, 400 participants with StD will be randomly assigned to an experimental group (n = 200) or a waiting‐list control group (n = 200). The experimental group will receive a 10‐min SPSRS video‐viewing intervention once daily for 5 weeks; when the intervention ends, the waiting‐list control group will receive the treatment upon request. The intervention's primary outcome will be the mean change from baseline on the Center for Epidemiologic Studies Depression Scale; secondary outcomes will include the mean change from baseline on the Kessler Psychological Distress Scale and the Generalized Anxiety Disorder seven‐item scale.

The results are presented according to the protocol.

This trial's confirmation of SPSRS's efficacy could lead to new StD intervention strategies and provide interventions tailored to patient needs.