I started wondering last night how much of my headspace weirdness could just be the dextromethorphan (DXM) in the NyQuil I've used to get to sleep a few times over the past couple weeks. If you don't read the labels on your medication (you really, really should), DXM is the active ingredient in every over-the-counter cough suppressant I've ever seen. It can also be used as a dissociative drug, as generations of high school students know, leading Erowid to have an information page on it. I'm taking it in normal doses, of course, probably even lower than listed on the package, but haven't you ever wondered why NyQuil kicks your ass the way it does?
Look at the ingredients, for starters: in one 15mL dose, there