Dew, based on guesses to this brainteaser and your replies to them, it seems to me that there is not enough information to solve it; i.e, what human attributes do humans retain as insects for purposes of this brainteaser? For example, do they still have human intelligence (I assume so, otherwise there would be no drugs to begin with)? Do they reproduce as humans or insects (if as the latter, then I think my #2 answer is a correct one)? Is their lifespan humanoid or insectoid? I think you need to share your assumptions about this "metamorphosis" with us.