Objectives To provide cost burden estimates and long-term trend forecast of mental disorders that need hospitalisations in Shanghai, China.

Design Daily hospital admissions and medical expenditures for mental disorder hospitalisations between 1 January 2011 and 31 December 2015 were used for analysis. Yearly total health expenditures and expenditures per hospital admission for different populations, as well as per-admission-per-year medical costs of each service for mental disorder hospitalisations, were estimated through data from 2015. We also established time series analyses to determine the long-time trend of total direct medical expenditures for mental disorders and forecasted expenditures until 31 December 2030.

Setting Shanghai, China.

Participants Daily hospital admissions for mental disorders of registered residents living in all 16 districts of Shanghai, who participated in workers’ basic medical insurance or the urban residents’ basic medical insurance (n=60 306).

Results From 2011 to 2015, there were increased yearly trends for both hospitalisations (from 10 919 to 14 054) and total costs (from US$23.56 to 42.13 million per year in 2015 currency) in Shanghai. Cost per mental disorder hospitalisation in 2015 averaged US$2998.01. Most direct medical costs were spent on medical supplies. By the end of 2030, the average cost per admission per month for mental disorders was estimated to be US$7394.17 (95% CI US$6782.24 to 8006.10) for mental disorders, and the total health expenditure for mental disorders would reach over US$100.52 million (95% CI US$92.20 to 108.83 million) without additional government interventions.

Conclusions These findings suggest total health expenditures for mental disorders in Shanghai will be higher in the future. Effective measures should be taken to reduce the rapid growth of the economic burden of mental disorders.