Smartphone App Used to Reduce Depressive Symptoms in Patients with Comorbidities in Low- and Middle-Income Countries

February 2022

Researchers noted that affordable interventions are needed in low- and middle-income countries that do not have enough trained personnel to treat patients with mental health conditions. Digital interventions show promise for improving depressive symptoms, but most studies have been done in high-income countries. These studies have also shown that the presence of chronic comorbidities may reduce the effectiveness of digital interventions for mental health.

The researchers previously published studies describing a digital intervention for depressive symptoms they call CONEMO (emotional control). CONEMO is a user-centered smartphone app that encourages users to find activities they find pleasant or meaningful, an approach called behavioral activation. The use of the app can be supervised by nurses rather than mental health specialists.

In the new study, the researchers tested the efficacy of the app in reducing depressive symptoms in patients with comorbidities. They took advantage of existing programs in Brazil and Peru to treat either hypertension or diabetes in public healthcare facilities to find patients with depression. People enrolled in one of these programs were screened for depressive symptoms using the Patient Health Questionnaire-9 (PHQ-9). Those with suicide risk, gestational diabetes, or hypertension at screening were excluded. Randomization was done by clusters of primary care units in Brazil and by individuals in Peru.

Users accessed the CONEMO app on their phones for a total of 18 sessions lasting up to 10 minutes each over 6 weeks. Nurse assistants met participants and contacted them twice before the sessions started. The primary outcome was a 50% reduction in the PHQ-9 scores from baseline after 3 months. There were a total of 596 participants in the digital intervention group and 604 in the control group who completed the 3-month assessment.

In both countries, the percent of participants in the digital intervention group who had a ≥50% reduction in PHQ-9 scores was significantly greater than in the control group at the 3-month assessment. The absolute difference in the percentage point change between groups was 12.1 in Brazil and 18.6 in Peru. By 6 months, these differences were no longer statistically significant, mainly due to further improvements in depressive symptoms in the control groups. Other assessments, such as quality of life and disability, generally followed the same pattern.

The authors concluded that their results show that digital interventions could be useful in low- and middle-income countries that do not have a sufficient supply of mental healthcare specialists: “An 18.6% increase in response rates, compared with the control condition as seen in Lima, would result in a sizable reduction in depressive symptoms if this digital intervention were implemented at a larger scale. Even in Brazil, with a smaller increase of 12.1% in response rates, this brief and low-intensity digital intervention might have a clear public health effect in a country with a notable treatment gap for depression,” they wrote.


Araya R, Menezes PR, Claro HG, et al. Effect of a digital intervention on depressive symptoms in patients with comorbid hypertension or diabetes in Brazil and Peru: two randomized clinical trials. JAMA. 2021;325:1852-1862.

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