It's malic acid. And it probably doesn't do any more harm than any other carbohydrate (which is what it is - a sugar). Energy drinks are primarily "fueled" by caffeine. The additional vitamins, Amino Acids and sugars in it are window dressing and there is no evidence that they add anything to the "energy" derived from the caffeine. You are already on adderal-talk to your doctor about it before taking caffeine.
Not sure. I'm not sure what "matalic acid" is - you may have misspelled the word. I'm not a big fan of five-hour energy drinks for this reason. It's like slamming a cup of coffee. There is a similar amount of caffeine in a 5-hour drink as a cup of coffee. The difference is you do the 5-hour drink as a "shot", whereas you drink a cup over 20 minutes or so.