EDEN Syndrome

The EDEN Syndrome (症候群) is a mysterious disease in Digimon Story: Cyber Sleuth. It is said to be caught by heavy users of Cyberspace EDEN. Although it's said to be caused by brain nerves being overloaded with data due to illegally modded "s", as well as "Brain Jack" made by Hackers, it is actually caused by the mental data of a person being consumed by an Eater.

Digimon Story: Cyber Sleuth
The EDEN Syndrome has started spreading through the Real World. To prevent mayhem, infected patients are put in quarantine in special hospitals. A person dear to Yuuko Kamishiro has been infected by it, and she's working to save him or her. It is later discovered that this person is Yuugo Kamishiro, Yuuko's older brother, who fell prey to an Eater years ago during the EDEN beta test. During the test, in which Yuugo, Yuuko, Aiba, Nokia Shiramine, and Arata Sanada took part, a connection was made between EDEN and the Digital World, allowing the children to cross over and encounter Digimon for the first time. However, the connection had also attracted an Eater to investigate, and the Eater attacked Yuugo while the others escaped. As a result of Yuugo's mental data being consumed, he was the first victim of EDEN Syndrome. Altered by the consumed mental data, Eaters would go on to attack others within EDEN as well.

Aiba also becomes a victim of EDEN Syndrome, but is unique in that their mental data was only partially corrupted following an Eater attack, which resulted in their mental data acquiring a Data Body.

When the portal between the Digital World and the Real World is opened, Eaters are able to come through and consume people's mental data in the Real World as well, which causes cases of EDEN Syndrome to occur outside EDEN for the first time.

Following the defeat of the Mother Eater, the mental data of all Eater victims is released and they begin waking up from EDEN Syndrome.