The ADDC is a part of The Medical Institute, an institution within the Ministry of Health, Labour, and Welfare. It was formed in 2002 by Kaoru Ichinose, a politician who later became the Vice Minister of Health.
The complex sits atop a desirable plot of land sought after by Shigeru Kajihira, who employs the help of then vice-director of the ADDC, Toru Hashiki to close the center and allow the use of the land for redevelopment.
This all changed in 2017. After the public announcement that research into Alzheimers Disease treatment had led to the development of AD-9 , a potential cure, the government gave the ADDC a blank check to continue their work. As a result, Kajihira's plot to see the ADDC shut down was put on hold. Hashiki, who suspected that the AD-9 research was fraudulent and merely served as a convenient excuse to keep the ADDC in operation, was found badly beaten in a Kamurocho alley in mid-2018 and died three weeks later.
In a flashback sequence to 2015 during Chapter 5: Days Gone By, Koichi Waku, a long-term Alzheimer's patient on the ADDC's general ward, has died. The janitor Shinpei Okubo is suspected of killing him, but he protests his innocence, and Takayuki Yagami, his defence lawyer, believes him. He comes to the ADDC to investigate the murder, shown around by nurse Emi Terasawa. Despite his own mentor Masamichi Shintani believing Okubo's guilt and saying as much during their investigation, Yagami manages to find the evidence that would lead to Okubo's acquittal.