Mental and physical non-communicable diseases (NCDs) coexist, because they share common environmental and behavioral risk factors. The treatment gap for common mental disorders, such as depression, anxiety, and substance use, is large compared to other NCDs.

To determine the prevalence and treatment gap of common mental disorders among patients with non-communicable diseases.

The community-based cross-sectional study was conducted in the rural parts of East India, in people aged 30 years and older with NCDs. A simple random sample was chosen to select the villages and participants. Eligible participants administered with screening and diagnostic questionnaire for depression, anxiety, and substance use. Those diagnosed with mental disorders were again assessed for treatment status in the last 12 months. Non-receipt of treatment was considered as treatment gap.

A total of 515 participants were included in the analysis. The overall prevalence of common mental disorders among the study population was 46.4% (95% CI 42.0–50.8), and excluding substance use, the prevalence was 11.7% (95% CI 9.0–14.7). The treatment gap for common mental disorders among patients with non-communicable diseases, including and excluding substance use, was 98.3% (95% CI 95.8–99.5) and 93.3% (95% CI 83.8–98.2), respectively.

The prevalence and treatment gap of common mental disorders among persons with NCDs was high. Public health interventions need to be emphasized for the integration of mental health care into NCD care.