depression
"I took fluoxetine for chronic depression and anxiety. At 10mg, just had a little dry mouth. At 20mg, it began to work amazingly on my mood. I had experienced a major emotional, life-changing event just a few days prior, but after taking 20mg for a few days, I felt great. I didn't realize how wonderful I could feel after 5  years of recurring depression and anxiety. Eventually, the side effects just got to be too much though. The most obvious one was the awful insomnia. I woke up in the middle of the night and could not get back to sleep every single night within a week of upping the dose. It affected me so much I had to take a sleep medicine. After a few weeks, I started to have vivid dreams and had trouble differentiating them from reality."