For me, the main problem was major depression. My anti-depressant is helping me know. I've also been on ritalin for a short time. It helps alot, but you still have to decide to sit down and stay at your desk. For me ritalin was a great short term fix until I got my depression under control.
Depression has a lot of ADD symptoms, inability to concentrate, reduced memory, some anxiety.
I am quite sure now that I have some sort of mental disorder. I cannot complete any single task since I was a little kid. Not only that, procrastination is extreme with me at times. I am easily distracted. I am 20yrs old, I have problems completing tasks eventhough everybody considers me intelligent.