First thing I did in this thread was CTRL-F "chantix".
This was like years ago, thank god: First four days, didn't feel much of anything. Over the course of the next four or five days, started feeling progressively more and more existentially unsettled. Can't name it, can't put a finger on it beyond that. "Existentially unsettled". Mornings start going from waking up sleepy, as usual, to waking up feeling like I snapped out of a nightmare I can't (or don't dare) remember. Started noticing scratch marks on myself when I woke up and, once, that I'd bitten my lips and the inside of my cheeks.
So, almost two weeks into it, I go to bed and woke up at 4am out of the following dream: I was dreaming that I was a 60-foot tall worm-shaped creature, the front half a giant featherless and flabby, gray-skinned cockatrice and the back half was an enormous centipede's body with segments as wide as a car. Where they sort of joined up were at least one pair of suitably monstrous human arms. I was slithering-marching down a street, beaked head rising up above most of the buildings in a city bathed completely in red light, fire and screams. And as they came into reach, I would pick people up, lift them over my giant chicken demon's head and pull them apart like fresh bread, bathing me in their gore. Literally, I remember the intent was to bathe in the gore of everyone, coat myself with it. Worse, it was...righteous. Like I was some apocalyptic beast. And after each self-christening, I would let out another piercing, warbly roar, a thunderous Shepard's tone to let everyone know that I and judgement would soon consume them.
I sat up (covered in sweat), went to the dresser, grabbed the package with the Chantix in it, threw it in the wastepaper basket in my bedroom and grabbed some trash from under it and covered it.
I was afraid to go back asleep so I just stayed up and went to work tired. I can only imagine what the other dreams must have been like to have caused the scratching and cheek biting. Never felt suicidal or anything like that but discontinued it immediately because I didn't want find out what else that shit had in store for me.