Funding for this research was provided by:
National Natural Science Foundation of China (81574098)
Received: 27 May 2020
Accepted: 7 March 2021
First Online: 26 March 2021
: This study was conducted in accordance with the tenets of the Declaration of Helsinki and was approved by the ethical committee of the National Natural Science Foundation of China. The research did not directly involve any human body. Patient data were extracted from monthly reports maintained by Shandong Mental Health Center. All individual-level data were anonymous.
: This manuscript is approved by all authors for publication.
: The authors have declared that no competing interests exist.