Neelix: And that's not all. Ensign Parsons ordered his pejuta cold.
Doctor: So?
Neelix: He always drinks it hot. Hot! With lemon. But not today. Today it's cold pejuta, hold the lemon.
Doctor: Mister Neelix, just because a man changes his drink order doesn't mean he's possessed by an alien.

Cathexis, Star Trek Voyager