Using a Smartphone App to Reduce Cognitive Vulnerability and Mild Depressive Symptoms

Depression is one of the major challenges worldwide, with significant increasing personal, economic, and societal costs. Although empirically supported treatments have been developed, they are not always available for patients in routine clinical care. Even when patients are adequately treated, they do not always respond to treatment and/or face a significant risk for recurrence. Therefore, effective and wide accessible strategies to prevent the onset of the very first depressive symptoms are necessary. Mental health apps could prove a valuable alternative for that. Although preliminary research has indicated that apps could be useful in treating depression, no study has attempted to test their utility in preventing depression symptoms. The current study aims to contrast the efficacy of a smartphone app in preventing depression compared against a waiting list condition. The app includes self-help materials and exercises based on cognitive behavioral therapy (CBT) for depression, presented in a tailored manner and incorporating gamification elements aimed at boosting the motivation to use the app.

This study protocol is the first that capitalizes on the ubiquity of smartphones to large-scale dissemination of CBT-based strategies aimed at preventing depression in nonclinical populations. The objective of this study is to test an app designed to decrease general cognitive vulnerability and promote engagement in protective, adaptive activities, while counteracting the tendency of premature dropout (through gamification and customization).

Trials design. This study will include two parallel-randomized trials, with pre-post measurements. The designs of the trials will be similar and compliant with the CONSORT guidelines. In the first trial the efficacy of the preventative version of the application will be tested against a wait list control group, in a healthy sample of participants. In the second trial the efficacy of the app will be tested against a wait list control group, in a sample of participants with mild depressive symptoms.

Participant timeline. Potential participants will be assessed for eligibility through an initial assessment of depressive symptoms. The initial assessment phase consists of administration of the PHQ-9 and a short screening telephone interview. Subsequent assessments consist of all the instruments presented in the Outcome measures section. After the initial assessment, the participants meeting inclusion criteria will be randomly assigned to one of the two conditions: immediate online intervention condition (Group 1) or the delayed-intervention condition (wait-list) (Group 2).

Participants assigned to Group 1 will be given access to the online application along with explicit instructions regarding the use of all of its sections. Participants will be given 4 weeks to complete the intervention, during which time weekly messages will be sent out to them. Messages include regular assignments designed for a complete and thorough use of the application's courses and exercises, and encourage the review of materials whenever possible. However, participants are free to use the application at their own pace.

Participants in the delayed intervention group (Group 2) are placed on a wait-list for 4 weeks.

Sample size. A a total number of 50 participants per study (i.e., 50 participants without depressive symptomatology, and 50 participants with mild depressive symptomatology) was estimated based on previous studies testing mobile phone applications for depression that reported large within group effect sizes. The calculation of the sample size was conducted with G\*Power 3.1. for ANOVA (Repeated measures, between factors), assuming an alpha level of 0.05, a statistical power of 0.80, and a large effect size (Cohen's f = 0.355).

Recruitment. Possible participants are approached through presentations at various events and ads in the media. Those interested in using the application are asked to provide their contact details and are subsequently contacted via e-mail, at which point the enrollment procedure is described. Initially, possible participants are invited to access the study's website and, after carefully reading the information package and informed consent, instructions to create an online account are given. The participants are then asked to answer a few demographic questions and complete the PHQ-9, to determine their eligibility for further evaluation. If eligible, a screening procedure is implemented. A short telephone interview screens out individuals whose participation in the study is motivated by problems other than their mood. Applicants who do not meet the inclusion criteria are informed via e-mail, thanked for their interest, given a summary score and interpretation for their PHQ-9 score. Applicants are encouraged to discuss their problems with a professional, if necessary. Information on how to reach one - a clinical psychologist or psychotherapist - is also provided. Licensed, certified clinical psychologists recruit prospective participants into the study. Media avenues (e.g., social networks, dedicated websites) are used for recruitment purposes. Additionally, clinicians from the private practice area are contacted for referrals.

Assignment to study group. The participants are assigned to one of the two trials, depending on their depressive symptomatology level (i.e., PHQ-9 score). Using the software Randomizer.org, participants are then randomly distributed to one of the trials' conditions. Randomization is performed by a research assistant using a simple (unrestricted) randomization sequence that assigns two unique numbers per participant; the number assigned is either 1 or 2, according to the number of the experimental conditions. To conceal the allocation mechanism, the same research assistant will monitor the assessments and allow access to the application for the participants in the delayed intervention condition (Group 2), after 1 month. The principal investigator and the statisticians running the data analysis will remain blinded to the study condition until the completion of the study.

Monitoring study implementation. Two clinical psychologists, members of the study team, screen for the risk of unintended effects or harm to the participants (i.e., clinically significant increase in depressive symptomatology, as measured by the CESD-R). The psychologists also monitor the weekly online evaluations and clinically interpret the CESD-R score of every participant. If the participant does not complete the CESD-R evaluation, a telephonic contact follows. If necessary, the supervisor can decide to interrupt the participant's access to the application and make a further referral.

Eligibility Criteria:
Inclusion Criteria:

* Romanian-speaking adults (18 years or older)
* Access to a computer, a smartphone (Android or iOS) and Internet
* A Patient Health Questionnaire-9 (PHQ-9) score of 4 or below (for the healthy participants sample)
* A PHQ-9 score no greater than 9 (for the mildly depressed participants sample)

Exclusion Criteria:

* Undergoing therapy
* Substance abuse problems
* Psychotic symptoms
* Organic brain disorders (e.g., dementia)
* Self-injury or harming others
* Serious legal or health issues that would prevent from using the app
* Reporting scores larger than 1 to Question 9 (suicidal ideation) on the (PHQ-9)