Study Protocol for a Smartphone Application-based Intervention for Subthreshold Depression

Study Overview
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Brief Summary
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The investigators plan to conduct a randomized controlled trial to examine whether a Smartphone-based Intervention improves subthreshold depression symptoms compared to no intervention. The purpose of this pilot randomized controlled trial is to investigate the feasibility of the final randomized controlled trial.

Official Title
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Study Protocol for a Pilot Randomized Controlled Trial on a Smartphone Application-based Intervention for Subthreshold Depression

Conditions
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Subthreshold Depression

Intervention / Treatment
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* Device: Smartphone Application


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 Years and older Males and females Center for Epidemiologic Studies Depression Scale score ≥16 Written informed consent prior to participation Owns a smartphone with the iOS® operating system Exclusion Criteria: Lifetime history of psychiatric disorders Currently receiving treatment for a mental health problem from a mental health professional Experience of a major depressive episode in the 2 weeks prior to the study, as ascertained using the Mini-International Neuropsychiatric Interview Vision or hearing deficits that negatively impact everyday life

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Smartphone Application<br>Participants watch a video using the Smartphone Application displaying positive word stimuli. | Device: Smartphone Application<br>* The experimental group will watch movies using the Smartphone application for at least 10 min a day for 5 weeks.<br>|
| No Intervention: No Intervention<br>No Intervention. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Depression severity as measured by the Center for Epidemiologic Studies Depression Scale (CES-D) score. | The CES-D is a 20-item self-report questionnaire used to measure depressive symptoms. The CES-D is a four-point Likert scale, with each item scored from 0 to 3. The total score ranges from 0 to 60 points. The higher the score, the stronger the depressive symptoms. | Change from Baseline CES-D at 5 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Psychological distress as measured by the Kessler Screening Scale for Psychological Distress (K6) score. | The K6 is a 6-item self-report questionnaire used to measure psychological distress. The K6 is a five-point Likert scale, with each item scored from 0 to 4. The total score ranges from 0 to 24 points. The higher the score, the stronger the psychological distress. | Change from Baseline K6 at 5 weeks | 
| Anxiety as measured by the 7-item Generalized Anxiety Disorder Scale (GAD-7). | The GAD-7 is a 7-item self-report questionnaire used to measure anxiety. The GAD-7 is a four-point Likert scale, with each item scored from 0 to 3. The total score ranges from 0 to 21 points. The higher the score, the stronger the anxiety. | Change from Baseline GAD-7 at 5 weeks |