Over the last few decades, studies have been investigating the impact of occupational stress complaints on workers’ mental health [1,2]. Currently, there is a pressing need for a greater understanding of gender as a social determinant of health in the work context [3]. According to the American Psychological Association’s report Stress in America: The State of Our Nation [4], women consistently report higher stress levels than men, are more likely to say they experience symptoms of stress, and have difficulty dealing with it. Several studies indicate that work-related factors may affect women and men differently and suggest that women may be disproportionately affected because of work and family roles [5,6]. Research from the World Economic Forum’s Gender Gap study showed that women work nearly an hour longer than men every day, when both paid and unpaid tasks are considered [7]. Therefore, these findings indicate that working women may experience more stress than men and that the sources of stress are related to the expected and actual roles of women in society. Considering the increasing numbers of women in the workforce, it is critical that more resources be directed toward reducing the negative effects of work stress on women’s health and well-being.

Some very successful programs in stress management are based on the principle of Mindfulness—a metacognitive ability, defined by Jon Kabat-Zinn as “the awareness that emerges through paying attention on purpose, in the present moment, and nonjudgmentally to the unfolding experience moment to moment” [8]. The mechanism of action for mindfulness may be explained through a set of 4 interacting components [9]: (1) attention regulation (sustained attention, with returned attention on the main object of focus upon distraction), (2) body awareness (focused attention on subtle bodily sensations to enhance attunement with one’s body), (3) emotional regulation (practice of nonjudgmental awareness of one’s emotional responses in the moment), and (4) change in self-perspective (detachment from the view of an unchanging self). Although research exploring the effectiveness of online mindfulness-based interventions (MBIs) is still in its infancy, a recent meta-analysis concluded that there is emerging evidence that online MBIs have the potential to improve mental health outcomes, most notably stress [10].

Although the mental health care system has traditionally focused more on treatment of mental disorders than on prevention, it is recognized that mental health is more than just the absence of mental illness. Positive psychology is the study of well-being, engagement, and optimal functioning, fitting well with the World Health Organization’s (WHO) definition of mental health: “a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community” [11]. The PERMA model proposed by Seligman [12] stipulates that happiness and psychological well-being is made up of 5 core components: positive emotions, engagement (similar to the concept of mindfulness), positive relationships, meaning, and accomplishments. Well-being has been shown to reduce the risk of developing mental health alterations or disorders [13,14]. Results from a meta-analysis of 51 positive psychology interventions with more than 4000 individuals revealed that such interventions do indeed significantly enhance well-being [15]. A number of studies conducted with adult [16] and younger [17] populations have shown improvements in well-being through the use of online positive psychology interventions. Technology-based self-care programs allow individuals to circumvent some of the limitations associated with traditional support methods, such as time, resources, flexibility, accessibility, and availability [18]. Indeed, this is in line with WHO directives recommending “the promotion of self-care, for instance, through the use of electronic and mobile health technologies” [19].

Mobile health (mHealth), which promotes the use of wireless technologies in health care, is one of the fastest growing fields within electronic health (eHealth) [20]. According to the Digital 2019 Q2 Global Digital Statshot report, 5.11 billion people own a mobile phone, which represents 66% of the world’s population [21]. About internet and mobile use in Brazil, the recently launched Digital in 2019 report [22] showed that more than 149 million out of the country’s nearly 212 million inhabitants are active internet users and that there are 215.2 million mobile connections in Brazil, which represents a penetration of 102%. Moreover, the report stated that 66% of all Brazilians are mobile internet users and that there is an average use of 34 mobile apps per month per smartphone in the country. According to the IQVIA Institute, there are currently more than 318,000 health apps worldwide, nearly double the number of apps available in 2015, with more than 200 new health apps being added to app stores every day [23]. Even with this substantial increase over the previous report [24], consumer Digital Health apps targeting wellness management still account for the majority of health apps (60%), and mental health remains the largest focus for disease-specific mobile apps (28%) [23].

The use of a mobile device makes it possible to intervene and interact with the participants within the context (ie, their work environment) and during moments of their daily life, which is a form of intervention called ecological momentary intervention (EMI). The most reliable method for investigating real-world emotion is experience sampling, which involves contacting people as they engage in their everyday activities and asking them to report their thoughts, feelings, and actions at that moment [25]. Therefore, app-based EMIs offer a versatile, multifaceted, and interactive way of promoting training, mindfulness, self-awareness, motivation, and environmental awareness within the context of everyday life. The near ubiquitous use of smartphone apps provides a vehicle for making EMI a widespread and effective way of promoting positive change in a large nonclinical, nontherapeutic population.

Although smartphones and mobile apps seem to be ideal tools in many aspects for providing instantly accessible interventions to promote health, the content of these apps must be based on systematic research, as without such content, any observed effects could be placebo or even harmful. Even though the availability and use of mental health mobile apps have grown exponentially in recent years, few have been thoroughly tested to provide robust scientific evidence regarding their efficacy in modulating behavior or promoting health [26-28].

From these considerations, we developed 2 apps and hypothesized that a well-being mobile app, composed of an 8-week program with 4 lessons per week—based on relaxation training, breathing techniques, guided meditation, and positive psychology principles—could be effective in reducing stress and increasing well-being among working women when compared with an active control app designed to encourage self-observation and evaluation of subjective levels of stress and well-being, for the same period and weekly frequency. Here, we report the results of a randomized controlled trial in which we compared a well-being mobile app and an active control app on improving well-being and reducing stress in a group of women working in a private hospital in São Paulo, Brazil. In short, the aim of this study was to evaluate whether it is possible to improve psychological health by promoting stress management and well-being using a mobile app.

The experimental design of this study and the format of the manuscript followed the Consolidated Standards of Reporting Trials (CONSORT) statement for reporting randomized controlled trials [29], its extension for nonpharmacological trials [30], and the CONSORT-EHEALTH checklist [31]. See Multimedia Appendix 1 for CONSORT-EHEALTH checklist (V 1.6.1). The trial was registered at ClinicalTrials.gov, number NCT02637414 (Flourishing App: Evaluation of the Effectiveness of a Well-being App for Mobile Devices), on December 11, 2015. This study was a 2-arm randomized controlled trial conducted in Brazil. Participants were randomized using a 1:1 allocation ratio to 1 of the 2 parallel groups: (1) well-being mobile app based on relaxation, breathing, meditation, and positive psychology principles and (2) control app, containing only instructions to self-observation for 20 min and recording of subjective levels of stress and well-being. Both apps were developed in Brazilian Portuguese language and were fully automated without any human involvement. Longitudinal assessments were conducted at baseline, midintervention (4 weeks after baseline), and postintervention (8 weeks after baseline).

We conducted this study at a large private tertiary care hospital in São Paulo, Brazil, from June 2016 to May 2017. We used mailing lists and intranet ads to invite hospital staff to participate in the study. Individuals were included if they met the following inclusion criteria: women aged between 20 and 60 years who had completed high school, owned a mobile device with either an iOS or Android operating system, and were available to participate in the 8-week training program. Potential participants first provided demographic data through an initial registration form, and those who were selected were then randomly assigned to 1 of the 2 groups (control or intervention). After that, they were given access to 1 of the 2 apps and a tutorial with instructions for its use. Excluded participants were informed via phone or email.

Primary outcome measures were taken at baseline (t₁), midintervention (t₄=4 weeks after t₁), and postintervention (t₈=8 weeks after t₁). We assessed stress perception using the Brazilian Portuguese version of the 10-item perceived stress scale (PSS-10) [42,43] and subjective well-being with the Brazilian Portuguese version of the 5-item World Health Organization Well-Being Index (WHO-5) [44,45]. These Web-based questionnaires were applied using Google Forms through a link sent to participants via email. We also used an in-app questionnaire to assess subjective symptoms of stress and well-being at work and overall during the previous 30-day period. Moreover, within the app, secondary measures were gathered 4 times a week during 8 weeks, before and after the period of each class (intervention condition) or monitoring of perceptions (control condition) by assessing current subjective symptoms of stress and well-being.

In September 2016, 653 individuals were enrolled in the study through the website and were then screened for eligibility. Among these potential participants, 163 were excluded (because they did not complete baseline measures or were unable to access the app) and the remaining 490 were randomized (see Figure 1 for a flow diagram). We excluded an additional 185 participants at the 4-week follow-up and another 79 at the 8-week follow-up because of noncompliance with the experimental protocol (ie, completed less than 75% of each module). Participants who did not complete t₄ and t₈ assessments were equally distributed between groups (t₄: control group=34.6% [83/240] and intervention group=40.8% [102/250]; X²₁=2.0; P=.16; effect size for chi-square test ϕ=0.064; t₈: control group=29.9% [47/157] and intervention group=21.6% [32/148]; X²₁=2.7; P=.10; ϕ=0.095).

Table 1 and Figure 2 show the baseline sociodemographic and outcome score data for both groups, respectively. Overall, the mean age of the participants was 34.6 (SD 7.62) years; 53% (n=161) were married or lived with a domestic partner; 45% (n=137) had a graduate degree; and 65% (n=197) were professionals other than nurses, physicians, or professionals in leadership positions. On average, PSS-10 scores were 22.73 (SD 6.69), and WHO-5 scores were 10.75 (SD 5.14). As seen in Table 1 and Figure 2, baseline characteristics were equivalent. See Multimedia Appendix 4 for mean (SD) and median (p25-p75) values.

The primary aim of this study was to evaluate the effectiveness of a mobile app promoting stress management and well-being for working women. To this end, we conducted a 2-arm randomized controlled pragmatic trial with female employees at a private hospital using a long period program (8 week), a self-selected sample, and standardized questionnaires. The pragmatic trial is designed to test the effectiveness of an intervention in everyday life to maximize applicability and generalizability [55]. Groups were homogeneous regarding baseline characteristics, and although both groups showed a significant increase in general well-being, only the intervention group presented a significant increase on the well-being index (WHO-5 scores) and work-related well-being, as well as significant decreases in perceived stress (PSS-10 scores), work-related stress, and general stress. In addition, participants who used the well-being mobile app reported a significantly greater reduction in stress levels and a significant increase in well-being levels after each daily activity than participants who used the active control app. These results indicate that the well-being app was more effective at reducing employee stress and improving well-being levels.

One of our primary outcome measures was the PSS-10, the most widely used psychological instrument for measuring the perception of stress. Our results showed that participants from both groups were severely distressed at baseline scores (control [̄=22.9; SD 6.24] and intervention ̄=22.6; SD 7.16]), and only the intervention group presented a clinically significant change in the PSS-10 score (−6.15 points, on average) at the end of the 8-week study period, reaching symptom-free status (PSS-10=15.6), as defined by Ebert et al [48].

The other primary outcome measure used in this study was the WHO-5, one of the most widely used questionnaires to assess subjective well-being. The WHO-5 baseline score for both groups was approximately 43%, which indicates reduced well-being. After 8 weeks, the control group had a WHO-5 increase of approximately 6%, whereas improvement for the intervention group was almost 17%. Therefore, the difference in WHO-5 scores between groups was approximately 11%, which is clinically significant. However, at the end of the 8-week study period, the participants in the intervention group still had mean WHO-5 values (̄=14.93; 59.72%) below the general population reference level of 73.37% [45].

In the field of stress research, many studies use the WHO-5 to assess a wide variety of aspects including links between working conditions and well-being [56], the association between psychosocial working conditions and psychological well-being [57], as well as the association between workplace stress and well-being [58]. Our results corroborate the findings of Goa et al [58], who found that approximately 35% (n=977) of a total of 2796 employees presented low well-being scores (WHO-5 < 50) and that women, younger workers (<40 years), workers with high educational levels, and those with higher levels of job stress reported higher rates of poor mental health.

Several factors may contribute to the results obtained in this study. First, we applied an app-based EMI to intervene and interact with the participants in their work environment and during moments of their daily life. In addition, our system has been designed to ensure that participants respond to questions in the moment, that is, soon after being alerted to do so. This is a great advantage in relation to (1) surveys that require people to make retrospective and often generalized judgments, which tend to be affected by memory limitations and recall biases [59], and (2) laboratory experiments that do not occur within the context of a person's daily life, as we know that context can influence a person’s states and responses [60]. Self-monitoring has long been known to raise self-awareness and promote positive behavioral development under certain conditions [61,62]. Specifically, it has been theorized that being asked questions about one’s momentary states, experiences, behaviors, and/or thoughts close to the time and context of their occurrence may help one become more mindful of their occurrence, thereby providing opportunity for change [63]. Although it was only recorded as self-monitoring, participants in the control group reported that measuring stress and well-being levels before and after 20 min made them aware of changes in their physiological state (ie, they became more aware of their thought processes and more reflective). This could explain the increase in general well-being also observed in the active control group.

Second, our 8-week training program was built on the basis of 2 central approaches aimed at reducing stress and improving well-being. As described previously, meditation was one of those foundations. Studies involving smartphone delivery of mindfulness interventions focusing on workplace stress [64,65], well-being [41,66-68], and depression [69] showed comparable results to previous traditional interventions focused on the same outcome variables. The advantage of the smartphone interventions is that they are more rigorous because of instruction standardization across participants in the experimental group, the inclusion of active control materials participants expected to benefit from, and objective measures of adherence (provided within the app) rather than self-report. The other foundation was positive psychology principles. A recent meta-analysis revealed that 67% of positive psychology interventions are delivered in a self-help format, sometimes in conjunction with face-to-face instruction and support [34]. It is already known that a shotgun approach involving multiple and different positive exercises may be more effective than engaging in only 1 activity [70]. In our well-being mobile app, we used a combination of exercises and information to develop skills across different positive psychology domains, besides providing information about the benefits of increased well-being. From a public health perspective, self-help interventions can serve as cost-effective mental health promotion tools to reach large target groups that may not otherwise be reached [71].

Third, the theoretical basis of the intervention was confined to evidence-based components, consistent with the recommendations presented by Bakker et al [27] to create better and more rigorous mental health apps (MHapps). The chosen strategies were as follows: (1) focusing on nonclinical mental health, psychological well-being, and coping abilities, aiming to increase accessibility, enable preventive use, and reduce stigma, therefore avoiding the harmful effects of using mental illness labels [72]; (2) using self-monitoring and self-reflection—core features of many evidence-based psychological therapeutic techniques—to promote psychological growth and enable progress evaluations [73], with the advantage that MHapps make it possible for users to record self-monitoring data during their usual daily routines, while undergoing challenges or directly experiencing stressors [18]; (3) applying behavioral activation (ie, encourages individuals to engage in physiologically activating and psychologically rewarding activities) to boost self-efficacy, psychological well-being, and a repertoire of coping skills, since an app may promote self-discovery by encouraging an activity and then prompting reflection on the experience immediately after [74]; (4) presenting brief and passive psychoeducation to develop mental health literacy, in other words, to teach the participants about psychological processes underlying their distress and inform them about resources available to manage it [75]; (5) using real-time engagement to allow users to seek help for psychological challenges at the time they experience distress or soon after, thus opening new learning opportunities and applying coping strategies in ecologically valid contexts [76]; (6) promoting activities explicitly linked to specific mood problems to enhance understanding of cause-and-effect relationships between actions and emotions [77]; (7) using gamification—the use of “game-based mechanics, aesthetics and game thinking to engage people, motivate action, promote learning and solve problems” [78]—and intrinsic motivation to encourage app use via rewards and internal triggers, positive reinforcement, and behavioral conditioning, emergent approaches that may help counteract motivation problems and yield additional well-being outcomes; (8) providing reminders (email and push notifications) as external triggers for engagement, aiming to increase adherence and reduce dropout from self-help interventions [79]; and (9) conducting an experimental trial to establish the app’s efficacy before recommending it as an effective intervention.

Donker et al [26] systematically investigated the effectiveness of MHapps. Only 8 papers (describing 5 apps) were identified as providing scientific support for MHapps. Only 1 of these was a self-contained app, whereas the other 4 required input from a mental health professional. Unfortunately, none of these apps is currently available in app stores. These findings revealed the lack of experimental evidence for MHapps, of which hundreds are available. Despite the small number of studies included in their review, Donker et al [26] concluded that although apps have the potential to benefit those with poor mental health, further studies are needed to fully understand their usefulness and effectiveness. In summary, our results show that the intervention improved subjective symptoms of well-being and reduced stress through a wide array of evidence-based techniques that were delivered via a simple, enjoyable, intuitive, and interactive design. The simplicity of a program’s interface and ease of navigation significantly influence users’ perception of the quality of Web-based mental health interventions [80]. Our results corroborated the key outcomes observed by Coulon et al [81] that evidence-based, transparent, functional, and user-friendly apps may engage patients in effective stress reduction strategies.

Despite the proven efficacy of internet-based mobile-supported mental health interventions, high attrition rates are observed [66,82]. Nonadherence is a common issue in online psychological interventions and may reduce the effectiveness of an intervention [83]. A systematic review of attrition rates from internet-based intervention programs in which contact with a therapist was minimal reported an average dropout rate of 31% (range: 2%-83%) [84]. These data suggest that this trial had an acceptable attrition rate (54%) relative to other eHealth programs. Unfortunately, it is difficult to compare adherence levels of this trial with those of other internet-based stress management interventions because few studies thus far have reported this information. The percentage of participants in this study who completed both conditions (46%) was similar to available intervention completion rates (eg, 37%, [85]; 44%, [86]; and 88% [87]). The adherence rates of a meta-analysis of online MBIs varied between 35% and 92% [10].

Participants who adhered perceived the intervention as manageable and felt that they had learned useful strategies. On the other hand, many nonadherent participants declared that it was not easy to make time to do the exercises, although the self-help intervention helped them recognize the importance of self-regulating attention on their daily activities and finding personal space to relax. For this reason, it is critical to analyze the potential outcomes of traditional protocols delivered by new technologies. This critical investigation allows a better understanding of whether self-help mobile apps can be beneficial to users who are seeking well-being training to obtain better mental health.

Improving adherence is a high priority for internet interventions, as higher usage rates are associated with significant improvements in well-being [17]. Our mobile app used a one size fits all approach, which may not have been appropriate for a large group of people. Previous research indicates that providing support has a positive influence on adherence and enhances the effectiveness of online interventions [10,88]. Therefore, offering complementary instructor guidance to participants may potentially improve adherence and outcomes; however, instructor involvement is costly and may restrict the intervention’s scalability. These barriers may be partially overcome by using automated support. Automated support has been shown to improve intervention adherence and effectiveness [89].

The authors would like to highlight that this is a well-being and stress reduction educational app and that people suffering from mental disorders or whose symptoms are difficult to manage should seek support from a mental health professional. We would also like to emphasize that this app offers an initial experience in the field of self-care with introductory classes in meditation, relaxation, attention, and positive psychology topics. Although it may be an ideal tool for those who do not have time to attend regular classes, it is not intended to substitute the guidance of experienced/certified instructors for people interested in deepening their practice.

To interpret the results reported in this paper, some limitations should be taken into account. First, the main limitation of the study was that participants were not blinded, which may have increased bias. However, the designed study provided evidence of a pragmatic self-care intervention. Second, for feasibility reasons, the answers were self-reported. Third, we included only women and the volunteers self-selected into the trial, which limits the generalizability of the results. These limitations, however, should have minimal impact on the validity of the data, given the number of strengths of this study (eg, large sample size, use of an active control group, objective measures of intervention adherence, app developed for both Google’s Android and Apple’s iOS mobile operating systems).

Future research should aim to replicate the results of this trial and investigate variables that may affect outcome and adherence. Personalization and tailoring intervention to individual needs, from baseline stress and well-being levels, and interactive support could contribute to increased adherence and thereby to boost the effectiveness of the intervention. As all responses here were self-reported, integrating psychophysiological sensors with the apps and collecting biological measures, such as cortisol levels, would also strengthen the evidence of the beneficial effects of the well-being mobile app. Future studies are also necessary to investigate larger and more heterogeneous samples (in healthy subjects as well as clinical populations), to assess long-term efficacy measures (eg, including follow-ups of 1 or more years), and to better establish specific effects of this particular well-being mobile-based program.

Moreover, it would be interesting to test this protocol against the gold standard in the field (ie, face-to-face interventions) and assess which training format works best for which type of participant and under which circumstances. Although both formats may be equally effective, they may work differently on participants with different personal characteristics, and mobile-based interventions may be more advantageous in terms of efficiency and costs.

It is important to note that no single organization regulates parameters of app efficacy or transparency. The abundance of apps that have promising descriptions but are ultimately not well developed or maintained contributes to app overload and renders people vulnerable to misdirection and discouragement as they attempt to select and adopt effective self-management strategies. Well-planned studies will improve our ability to reach the potential of mobile mental health on both individual and population levels.

Our results indicate that the well-being and stress reduction app was better than the active control app at reducing employee stress and improving well-being levels. This trial contributes to the limited evidence available regarding the feasibility and efficacy of mobile-supported stress management and well-being interventions. Moreover, it is the first study to include an active control app group. The well-being mobile app presented here was highly effective in reducing perceived stress and improving mental well-being indices over a period of 4 and 8 weeks among women working at a private hospital. Thus, self-care mobile-based interventions may be used as preventive, easily accessible, and nonstigmatizing tools in a public health environment.