Starting or starting any medications can tilt a person into an episode up or down quickly or you might just fall into a regular mood shift that is unique to you and it not be due to Lithium or any other psych med.

I have in the past stopped meds left and right and been okay , Stopping lithium? yeah that one was rough for some reason or maybe I was just due to swing outta control for a bit . Mixed for a few weeks with hellish withdraws.. Funny never had a withdraw off an AP but Lithium? yep and it sucked.

It is usually best to taper off Lithium so that your not just going cold turkey and of course have to say .. talk to your Pdoc about it