Background Food insecurity poses a substantial threat to mental health. However, there is limited understanding of how food-insecure adults experience mental health challenges and access necessary health services. We examined the association of food insecurity with mental health status, mental health service utilisation and general healthcare utilisation among US adults.

Methods A retrospective longitudinal cohort study was conducted to analyse data from 9906 US adults participating in the 2016–2017 Medical Expenditure Panel Survey. Outcomes included mental health status, mental health service utilisation and general healthcare utilisation. The primary independent variable was food insecurity measured using the 10-item Food Security Survey Module. Two separate models were used: A lagged-dependent model and a fixed-effect model.

Results The lagged dependent model showed that food insecurity in 1 year was associated with a higher likelihood of reporting mental health symptoms based on the Patient Health Questionnaire and the Kessler 6 Psychological Distress Scale (3.5 percentage points (95% CI: 1.3 to 5.8)) and self-reported poor mental health (5.8 percentage points (2.9 to 8.7)) in the subsequent year. However, compared with food-secure adults, food-insecure adults were no more likely to have outpatient mental health visits, specialty mental health visits or psychotropic medication fills. Moreover, food-insecure adults were 4.1 (1.2 to 7.0) percentage points more likely to have an emergency room visit than food-secure adults. These findings were consistent with the fixed-effect model.

Conclusion Food insecurity is associated with worse mental health. However, food-insecure adults may not access adequate mental health services and instead rely on emergency room visits.