insomnia
"I've been taking doxylamine succinate for about 10 years, and it works great, much better than diphenhydramine and other over-the-counter aids, and at a much lower cost than prescription sleep aids. I used to work the graveyard shift for years, and found that when I got a "regular" job, I just couldn't sleep all night. Tried everything, this one's the best. Take a half pill if it makes you feel groggy, but I can shake off the grogginess more easily than I can shake off exhaustion from lack of sleep."