I do believe that this includes most illness, including mental illness. It also means supplementing to make up for the deficiencies we are bound to have. This is a complex subject that should not be tossed off lightly. So many people that I talk to vitamin C about scoff or say that it didn't work for them. Nutrition is not something you should try for a week and draw conclusions.
Every individual is different.
Different foods have very different consequences depending on who you are. The amount of supplementation depends on your biochemical individuality. To all those suffering from ADD, I ask that you look into the nutritional aspects of your treatment. Your brain is an organ and it is most sensative to its nutritional requirements. The nutrition we throw at our systems does indeed make us sick.