Appetite loss is normal for individuals on stimulant medications for AD/HD. As a mental health professional with over 25 years of community mental health experience, I have worked with numerous clients on various medications. All medications have side effects. You just need to take the good with the bad.
You have already seen improvements in your son’s behaviors. Therefor, if you would have asked me to consult with you, I would advise you that you have chosen the right medication. Long term stimulant use, unfortunately, has side affects.