Laced pot is a myth from the same school as the old tales about strychnine & rat poison in acid. Nobody's gonna put PCP or meth into a drug that costs far less to produce, where's the sense in that? Granted, with the price of opium at rock bottom, a lot of the soft dark hash around at the moment is opiated, but given the amount of soapbar around I wouldn't smoke bought hash nowadays anyway, unless I knew where it came from. If you've been getting sketchy off bud, it won't be because its been laced with anything, it'll be because commercial growers use all kinds of chemical ferts & organophosphate pesticides, which are neurotoxic (IHMO that's why there are apparent links between pot & mental health issues, its not the pot, its the crap that unscrupulous hydro growers pump into their plants to get maximum yields). They also cut it down far too early, don't dry it properly & rarely if ever cure it, all of which leads to a more edgy & harsh smoke. If you herb has been laced, it won't be by the growers or dealers, it'll be an acquaintance of yours spiking you (for which you will be totally within your moral rights to kick the living shit out of them, cos spiking's just about the most uncool thing you can do).