Because magnesium is a mineral that calms the nervous system, many people wonder if it is helpful for ADHD. There has been some research on the subject. A series of articles, mainly from Poland, in the late 1990s, indicated that children with ADHD had low levels of magnesium and that supplementing with the mineral might improve ADHD symptoms. There was no control group used in these studies, so the research is not convincing. Little research has been done since.
I think taking a reasonable dose of magnesium is fine if patients would like to try it. Sometimes it is helpful for relaxation and sleeping. Epsom salt baths are another way of getting magnesium, by absorption through the skin.