Blue Smartie Syndrome (BSS) is caused by ingestion of the additives E128 and E133. Other additives can cause similar effect, though the previous are the most used as examples. These are colours (Red and Blue respectively) found in many sweets and processed foods in varying amounts. They are known to cause hyperactivity in children, which can lead to INAD or hyperactive behaviour. Hence, it is extremely unwise to give smarties to hyperactive children, unless you want to prize them off of next door's TV aerial.
"What? Two BOXES? That's enough sugar for them to have a high of several hours!"