I had a prescription for Provigil. Acted like two cups of coffee without the jitters or urination, and without any impared behavilor. Modafinil may not have the same drawbacks as amphetamines, but I would expect some disconnect from reality after 5+ days awake.
A friend of mine took up smoking in the Navy. On long, cold, night watches everyone drank strong, bitter coffee to stay awake, then smoked tobacco to calm the jitters. In WWII, Germany had no access to coffee or tobacco. To keep going the troops "cooked" ephedrine into methamphetaine (redneck drug labs still use the "Nazi method" to turn sinus pills into crystalmeth). That explains a lot of the atrocities, like Malmedy.