Natural remission rates of depression among rural adult populations in India: multilevel analysis of the SMART Mental Health Project.

Background: Natural remission from common mental disorders (CMDs), in the absence of intervention, varies greatly. The situation in India is unknown.

Objective: This study examined individual, village and primary health centre (PHC)-level determinants for remission across two rural communities in north and south India and reports natural remission rates.

Methods: Using pre-intervention trial data from 44 PHCs in Andhra Pradesh and Haryana, adults ≥18 years were screened for CMDs. Screen-positive people (Patient Health Questionnaire-9 Item (PHQ9) or Generalised Anxiety Disorder-7 Item (GAD7) score ≥10, or a score ≥2 on the self-harm PHQ9 question) were re-screened after 5-7 months (mean). Remission was defined <5 scores on both PHQ9 and GAD7 and <2 score on self-harm. Multilevel Poisson regression models with random effects at individual, village and PHC levels were developed for each state to identify factors associated with remission. Time to re-screening was included as offset in regression models.

Results: Of 100 013 people in Andhra Pradesh and 69 807 people in Haryana, 2.4% and 7.1%, respectively, were screen positive. At re-screening, remission rate in Andhra Pradesh was 82.3% (95% CI 77.5-87.4%) and 59.4% (95% CI 55.7-63.3%) in Haryana. Being female, increasing age and higher baseline depression and anxiety scores were associated with lower remission rates. None of the considered village- and PHC-level factors were found to be associated with remission rate, after adjusting for individual-level factors.

Conclusions: Natural remission for CMDs vary greatly in two Indian states and are associated with complex, multilevel factors. Further research is recommended to better understand natural remission.