ABSTRACT
Background: Preventive interventions for subthreshold depression (StD) are essential to reduce the incidence of major depressive disorder. Our smartphone application presenting positive word stimulation in video (ie, Subliminal Priming with Supraliminal Reward Stimulation, SPSRS) was suggested to improve depressive symptoms in people with StD, although it is unclear whether it can immediately improve depressed mood. This pilot randomized controlled trial (RCT) aimed to investigate the preliminary efficacy of SPSRS application intervention on depressive mood in people with StD. Methods: Thirty-two participants with StD were randomly assigned to the experimental (n = 16) or control group (n = 16). The experimental group received SPSRS application intervention (10-minute video with positive word stimulation) and the control group received YouTube application intervention (10-minute video without positive word stimulation). Both groups used identical iPhones managed by the research team. The primary outcome was the change from baseline in depression-dejection on the Profile of Mood States 2nd Edition-Adult Short (POMS 2-A Short) after the intervention. Results: No participants dropped out of the study. The experimental group showed a small improvement in depression-dejection on the POMS 2-A Short score (adjusted Hedges's g = -0.32) compared to the control group. Post-hoc power analyses estimated a sample size of 56 per group (112 total) to evaluate depression-dejection on the POMS 2-A Short in a future full-scale RCT. Conclusion: SPSRS application intervention may be effective in immediately improving depressive mood in people with StD. A future full-scale RCT based on a formally calculated sample size should be conducted to replicate these findings.
ABSTRACT
BACKGROUND: Major depressive disorder (MDD) is an important public health problem. Thus, preventive interventions against subthreshold depression (StD), which is one of the key risk factors for the development of MDD, are important. The study developed a smartphone application (SPSRS) that improves depressive symptoms in people with StD by automatically presenting positive word stimuli during videos. The SPSRS application has the potential to improve depressive symptoms in people with StDs. However, whether it can immediately improve depressed moods in people with StD is unclear. The study presents a protocol for investigating the immediate effects of the SPSRS application intervention on depressed mood in people with StD. METHODS: The study is designed as an open-label, parallel-group, and pilot randomized controlled trial (RCT). Thirty-two people who meet the criteria for StD (Beck Depression Inventory-II score of 10 points or more and fails to meet the diagnostic criteria for MDD) will be recruited and studied. It compares the immediate effects of the SPSRS application intervention (with positive word stimulus in a 10-minute video; n = 16) and YouTube application intervention (without positive word stimulus in 10-minute video; n = 16). The primary outcome is the change in the score for the Profile of Mood States 2nd Edition-Adult Short after 10 minutes of intervention. The secondary outcome is the change in the State-Trait Anxiety Inventory State after 10 min of intervention. DISCUSSION: The pilot RCT is the first to evaluate the immediate effects of the SPSRS application intervention on depressed mood in people with StD. The results are expected to provide a preliminary outcome of the immediate effect of the SPSRS application on the depressed mood of people with StD and aid in planning a full-scale trial. TRIAL REGISTRATION: ClinicalTrials.gov; Identifier: NCT03864484.
