This disorder is similar to PTSD, Post Traumatic Stress Disorder, only it is triggered by the events leading up to and occuring during and after the Lost Series Finale.
Stress arises from the accumulation of snacks, drinks, and specific people before the event and the fears of missing the beginning.
During the Finale one will dissociate from reality and during the last 10 minutes will enter acute psychosis from either concentrating too hard or trying to combine six seasons of events to make sense of what is unfolding on screen.
After the Finale the viewer is exposed to Jimmy Kimmel's Lost special with a crying Matthew Fox, causing them to more deeply disassociate from reality thinking they are seeing Jack on an actual late night TV show because he cries so much. The appearance of Harold Parrineau, known as the character Michael, is almost too much to bear, as it brings back memories of when Lost was a good show and this can induce depression.
The stress during the actual events of the day are so intense they are not experienced until days, weeks, or probably in some cases years later.