Study Protocol Low Cost App-Based Intervention Dialog+ for Depression and Anxiety in Outpatient Psychiatric Settings: A Study Protocol for a Pragmatic Multisite Cluster Randomized Controlled Trial

Background Clinically diagnosed anxiety, and depressive disorders are widely recognised as the most common mental health issues in India, affecting approximately 15% of the population. With notable gender disparities, Tamil Nadu has some of the highest rates of depression in the nation. Despite the growing burden, countries such as India that fall within the low and middle-income countries (LMICs) continue to struggle with mental health services due to challenges in funding, a lack of qualified practitioners, and obstacles to putting evidence-based treatments like Cognitive Behaviour Therapy (CBT) into practice. Innovative, low-cost, and scalable approaches are needed to address this gap. This multisite, pragmatic randomized controlled trial (RCT) seeks to assess the feasibility, acceptability, and evaluate the effectiveness of DIALOG+, a low-cost, app-based, solution-focused intervention designed to enhance quality of life and reduce mental distress. While previously validated for psychosis and other chronic psychiatric conditions, this study aims to evaluate its potential for individuals with anxiety and depression in outpatient psychiatric services in India. Methods A pragmatic, multisite randomized controlled trial will be conducted across four outpatient psychiatric settings in Chennai and Puducherry to assess the feasibility, acceptability, and effectiveness of DIALOG+, a low-cost app-based intervention. Adults (18–65 years) with anxiety and/or depressive disorders will be randomly allocated to receive either DIALOG + together with treatment as usual (TAU) or DIALOG Scale alongside treatment as usual (TAU) over a 6-month period. The key outcome of this study is improvement in quality of life, evaluated through the Manchester Short Assessment of Quality of Life (MANSA). Secondary outcomes will include changes in depression and anxiety measured by the Depression, Anxiety and Stress Scale (DASS-21), Hamilton Depression Rating Scale (HDRS), and Hamilton Anxiety Rating Scale (HAM-A). Feasibility will be assessed through recruitment, retention, and intervention fidelity rates, while acceptability will be explored through interviews with participants and clinicians. Assessments at follow-up will be carried out at 3 and 6 months, and analyses will follow an intention-to-treat approach. Discussion If feasible, acceptable, and effective, DIALOG + for clinically diagnosed persons with anxiety and depressive disorders could represent a transformative, scalable solution to improve mental health outcomes in India and similar LMIC contexts. Trial registration The study is registered under Clinical trial registry-India (CTRI), and the registration number is CTRI/2025/08/092477.The registration was done on 6th August 2025.The URL of the trial registry record is https://ctri.nic.in/Clinicaltrials/rmaindet.php?trialid=133110&EncHid=16149.91763&modid=1&compid=19