But also my doctor gave me 10 mg of Adderall and it seem to do fine, but thought it could be increase to focus longer and better. So he gave me D amphetamine 20 mg with salt, but I felt it didn't do anything but make my teeth grind constantly. So he reduced it to 15 mg of with salt. Both of them does not seem to even catch my focus where the 10 mg did? I was wondering why. Appreciate your response.