I've used dxm about 10-14 times over about 4 months. (Avg. waiting time: 5-30 days). It's impossible for me to pay attention to anything, I have very bad memory, its absolutely impossible for me to retain information and I have ADD already. But I think I've added to it. Have I fried my brain? Will I be able to continue usage ever, as in every 2 months or so? Additional info: Im 15, I do not have access to ADD meds, my dxm doses are always 180-300. Last time using: Yesterday, 300mg.