text: I think it has something to do with side effects of too much of a certain neurotransmitter.  I've heard the term used to reference side effects of a drug (Aricept?).  This drug inhibits the activity of acetylcholinesterase.  This leads to a build-up of the neurotransmitter acetylcholine. Side effects of this effect are as follows:  S- excess salivation.  L- something involving tear production (can't remember the word) U- excess urination, D- Diarrhea.  The other D I'm not sure about.  Check on that definition for the word.  Good Luck!