The telepathic memory invasion was a telepathic weapon, analogous to rape, used by the Ullians. Until the late 21st century this form of mental violence was quite common on the Ullian homeworld. The invasion involved a telepath intruding into its victim's memories, either good or bad ones, and usurping these memories, so the victims were confronted with the telepath occurring in an always-repeated memory. After this the victim would fall into coma.
This horrific practice had ended as the Ullians became a more peaceful people. Unfortunately, new incidents were recorded in 2368 when Jev, a member of a group of Ullian telepathic historians, committed memory invasions on several planets, including Melina II, Nel III, and Hurada III; each of these incidents were either recorded as inexplicable comas or cases of the Iresine Syndrome.
The truth was discovered when Jev committed several invasions on crewmembers of the USS Enterprise-D. At first he tried to blame the invasions on his father Tarmin, but it was discovered that only Jev had been present during each of the now-explained comas on the planets. Jev was arrested and brought to the Ullian homeworld, where his punishment by his own words would be "quite severe". (TNG: "Violations")
Related phenomena Edit
It could be argued that any unwanted telepathic contact is a form of telepathic rape. In 2151 Tolaris, one of the Vulcan v'tosh ka'tur, forced a mind meld upon Sub-Commander T'Pol and infected her with Pa'nar Syndrome since he was not properly trained in the technique. (ENT: "Fusion")
During the Klingon crisis of 2293, Captain Spock forced a mind meld on Lieutenant Valeris to discover the names of the conspirators who had Chancellor Gorkon assassinated. (Star Trek VI: The Undiscovered Country)