I think I heard of this, as a rumor mostly. The two most added ingredients used in my circle were either opiates or Angeldust. Ugh, angeldust. Never went down that road.
I recall there were some chemicals sprayed on Mexican plants to kill them, but the growers allegedly harvested the crop anyway. The name of the chemical was Paraquat, I believe.
I'd believe it
more the reason to legalise marijuana, people woulds resort to chemicals to enchance their gears just for sales. but then again if it got commericalised it probably would anyway, just like they do top dressing on sunflowers to kill the crops deliberately upon harvesting and marketing it as 'lovely' and health focused (my arse!) all-natural sunflower seeds, worse its been sprinkled on loafs of breads that we eat everyday - nasty!
another thing sometimes cannabis is laced with pcp, (thats angel dust), what it is , it's actually horse tranquilisers...very potent...and it does a lot of damage.
a way of making sure its not laced with pcp is to check the bags, (or tear open the joint - roll with a new paper) is to look for white powders which usuallly falls apart from the grass. some cannabis might have white sticky stuff which are resins.
i dont smoke grass, i havent for the last 12 years. Even so that, that I smoked it, on a hindsight I dont approve of it for young people/ However, I still believe it should be legalised and make it for adults only at least 18 years of age, maybe at 20 if certain medical reasoning support that the 18-20 is still young at which the brain is still developing the morals judgement aspect.cognitive, or whatever (ive read it somewhere - sorry I forgotten what it is but its something like examples like; to do with ability to proper decisions regarding having sex and not thinking about the consequences of driving cars at reckless speed and so on. for this reasons i believe cannabis shouldnt be encouraged or made available (if legalised) for anyone untill say at least age of 20 or 21.
I am aware that each year strains of new seeds are picked and growth of next generation is alway stronger than the previous. It is a concern that the potency has gotten quite high that that in my opinion, the strength may be so strong that is no longer 'soft drug', liken to compare home brew beer to commerical ales or worse like hard liqour. Even if it was legalised, Id choose not to smoke it. Not that i dont enjoy it, theres other ways of enjoying life.
I also hallucinated the image of a woman at the end of the "wood" groaning. 
Hey, it was not planned. Never even tried sex when I did the mushrooms, until that time. I have not traveled on the Astral Plane for about 30 years now....
