I admit that I had a drug problem during high school. It lasted three months and it was a horrible time, big mistake it was. ADD/ADHD meds were the things I'd abuse the most. I remember waking up in the mornings before school, crushing Ritalin, and snorting them right before I headed out the door.
Over all it worked. It kept me alert and awake during school, I got things done faster, and I improved my perfomance in gym class.
However, it had horrible side effects. I started getting anxiety attacks and there was one incident where I had to run the mile during gym class. I took about 8 Concerta and was out on the track, doing really really good. Then out of nowhere I fell to the ground, started spasming and puking all over. It was a pretty embarrasing moment and the moment I realized I needed help.
So half a month in a mental health unit really helped me to get through it.
Speed as a recreational drug? Definitely not. I don't recommend it to ANYONE. It's a serious drug that has serious consequences. If you do have diagnosed ADHD and are prescribed the medications, then I encourage you to take it.