If interested in trying low-dose dextromethorphan, be sure to use cough preparations with dextromethorphan HBr as the ONLY active ingredient. Especially problematic is the additive polystyril; it will cause the DM to be slowly released rather than producing a "spike" in brain concentration that is crucial to its effectiveness (personal communication from Dr. J-S Hong). Also, keep the dose in the 3-5mg range. For easiest measuring, a cough syrup with 7.5 mg per 5ml (1 tsp) is best. That way, about 1/2 tsp is the correct dose. In this case more is NOT better, and take it EVERY night just before retiring.