Psychosis

Psychosis refered to a mental state where an individual lost contact with reality. Individuals suffering from this state were known as psychotic.

Early protests against the use of the transporter on Humans included the claim that it caused psychosis. Inventor Emory Erickson later recalled these concerns in a dinner on in 2154. 

In 2268, Commander Spock speculated to Captain Kirk that John Gill may have been suffering from a deep psychosis. 

In 2372, Lieutenant Tuvok asked The Doctor if Crewman Lon Suder was psychotic, but this possibility was ruled out by examining Suder's neurogenetic markers.