Temporal narcosis

From Memory Alpha, the free Star Trek reference

Temporal narcosis is a condition in which one experiences neurophysical stress when entering a separate time continuum unprotected.

Captain Jean-Luc Picard experienced a form of the condition when he was on the USS Enterprise-D, which was stuck in a temporal disturbance while helping a Romulan Warbird during a warp core breach. Lieutenant Commander Data described the condition to be similar to nitrogen narcosis. (TNG: "Timescape")