Hall of Infinite Doors

You proceed without your brain medicine and for a while you manage alright. You begin to think that maybe you do not need your brain medicine after all. Maybe it was just a placebo and you are completely fine without it. Then some subtle symptoms start to set in. Your vision starts to blur, you get strange phantom sensations across your body, and have occasional spasms and twitches. You ignore these symptoms since they are nothing more than minor inconveniences. After a few days, some severe symptoms set in, and you remember why you started taking your brain medicine in the first place.

The primary symptom is: