ADD is a disability under Section 504. Most scientists suspect the cause of ADD is genetic or biological, while also acknowledging environmental influences. Recent studies are examining the possibility of a chemical imbalance in the brain caused by birth injury, neurological damage or heredity. There is clear evidence of interference with developmentally appropriate social, academic or occupational functioning. Teachers play a critical role in the team of professionals required to make an accurate diagnosis.
Teachers are often the first professional to suspect a problem.
All joking aside, keep in mind that a teacher does not have diagnostic training and is not qualified to ensue or suggest that a child has a developmental or mental health problem. When you suspect a problem, make the proper referral to the people who have the training. Structure - Limit distractions, give clear instructions paired with written materials, provide checklists of work to be accomplished. Avoid angry and emotional responses or sarcasm towards the child. Don't do it.