narcolepsy
"I've been taking Ritalin for 3 years for Narcolepsy.  I was very unwilling to try it at first, but after much research and a push from my Dr, I was finally alert and able to think clearly for the first time in years.  I've had to alter my dose at times and currently take 10mg twice a day.  I work part-time and try to alter my lifestyle so I won't need to up my dose too soon.  I can't imagine life without it and hope it continues to work for years to come."