side effects and medicine

My son used to take a medication for adhd and it made him stutter among other things, he has been off of the medicine and doing great thanks to the diet, for about a month now. the only lingering side effect to this is stuttering, he still can't get the words out and now I am going to have to put him speech over the summer to help correct it. He is starting to get reduced off of his last medicine, once he gets off of it I will never go back, I am a firm believer in this diet and I will never do medicine on my children again when it comes to behavior.