This could explain many of the ME / CFS symptoms. Even a mild magnesium deficiency can cause : increased sensitivity to noise, nervousness , irritability, mental depression, confusion, twitching, trembling, apprehension, and insomnia. It will not show up on regular blood test . Magnesium chloride is needed to treat this deficiency. Read here: http://drsircus.com/medicine/magnesium. I am relaying research information only and not promoting any products .