insomnia
"This medicine is very effective for short-term use.  My experience is mostly good however, I do find that it does not work well when I have eaten recently.  You must take it on an empty stomach, I believe the Drug Facts say 1 hour without food before taking it.  When you take it with food, it sometimes does not absorb or takes longer to absorb.  Also, tolerance for me with this medicine goes up quickly so I try to only take it a couple of times a week.  I have not experienced any addiction symptoms by doing this.  

Side Note:  A lot of people who take it and report driving significant memory lapses are NOT TAKING IT AS DIRECTED.  You only take ONE (1) before bedtime and then you GO TO BED.  DON'T take it and go grocery shopping!"