Use of these drugs on a long-term basis is questionable. Safety of such long-term use is simply unknown, but many dangerous side effects have been increasingly observed. Ritalin , for instance, may provoke seizures and suppress growth, or it may cause angina, blood pressure changes, depression or any of a very long list of serious side effects. White spots on the nails could be a sign of zinc deficiency even when blood tests for zinc are normal. The best way of getting zinc is to optimize the diet.
Studies show that cognitive development can be impaired when there are low iron blood levels.
Deficiencies in B vitamins, particularly vitamin B1 and choline may also be involved. Since amino acids are the precursors to the neurotransmitters, low levels can lead to neurotransmitter deficiency. Higher than accepted levels may lead to neurotransmitter excess. One example of amino acid excess causing hyperactive behaviour occurs with the artificial sweetener, aspartame. Some children are highly sensitive to aspartame and scrupulous attention should be aimed at keeping this potential neurotoxin out of the child's diet.