Star Trek: 10 Weirdest Medical Cases

10. Patient: Various; 22nd And 23rd Centuries

Case: Psychic Exchange of Vulcan 'Katra'

Some doctors remain dubious about the medical validity of Vulcan mental techniques; the Vulcans themselves have proven less than forthcoming about them in the past, at times demonstrating overt prejudice before the re-discovery of Surak's writings in the Kir'Shara. In 2154, the katra of the father of Vulcan logic was temporarily housed by a human male when a dying member of the Vulcan 'Syrrannite' movement was forced to make the transfer in the Forge.

In 2259, two patients — a Vulcan female and a half-Vulcan-half-human male — participated in a 'soul-sharing' ritual during which an unintended, and exceptionally rare, katric transfer (a 'body swap') occurred. Fortunately, a doctor with advanced knowledge of Vulcan medicine was at hand to apply ground Nivallan sea urchin, crystals, and cortical stimulation to reverse the process. 26 years later, the same half-Vulcan-half-human patient, before his (temporary) death from acute radiation syndrome, effected a katra transfer on a human male present at the scene.

The effects of Vulcan 'synaptic pattern displacement' can vary from patient to patient, but humans may experience personality and behavioural changes, altered mood, involuntary recurrent memories, and eventually death. 'Treatment' requires the Vulcan 'fal-tor-pan' ritual to extract the offending katra.