While we're on drugs, why not a look at China Miéville's Embassytown, in which an unusual one plays a big role? This isn't quite an AFOE "Premature Evaluation" as I'm actually reading it, I just haven't finished it yet. A couple of points...
Pass by reference, not by value
This is the big-idea high concept here. It's sci-fi where the sci is linguistics, and fairly hard science fiction too. The aliens - and one thing that stands out is that we've got some seriously alien aliens here - are creatures that are comparably intelligent with humanity and indeed with a couple of other species and an occasional unusually bright robot, but who don't make use of a symbolic language.
As a result, the Sapir-Whorf hypothesis holds good for them - words are their own referents, language is limited by perception, and action is therefore constrained by language. One of the first results of contact between them and us is the development of what is essentially a creole, back-porting elements of symbolism into their vocabulary. This offers huge new intellectual possibilities but also a really awful failure mode.
After all, it's not as if they can't hear people or things speaking their language if it obeys their rules. The result is a little like a catastrophic, and accidental, buffer-overflow attack. Stuff leaks and gets incorporated into their internal thought processes.
Addiction and performance
Addiction is not a state of being, it's a relationship. This is why people rarely commit murder to get hold of coffee. It's the economic relationship, not the drug physiology, that does the work of corruption, and that works for the supplier as much as for the addict. When the aliens become dependent on a very specific product the humans can provide, this might sound like a grant of absolute power. It doesn't turn out very well for the humans, for just the reasons that suggests.
Similarly, people do the same sort of thing with their dependencies on each other. It's the diva mindset - when you can't tell "I need them" and "They need me" apart.
In part this is a love letter to diplomatic culture in its weirdness and anachronism and necessity. It was fashionable a few years ago to say that the whole thing had outlived its purpose. There were a couple of versions of this. One was that as Prime Ministers X and Y could just phone each other or fly off and meet, there was no need. This was astonishingly stupid and naive and the people who pushed it - Simon Jenkins for example - should have known better, knowing as they did just how much preparation goes into summit meetings and how journalists covering them generally start, the day before the meeting, by reporting what is likely to be in the communique as the diplomats have already drafted it.
Another, less idiotic but more pernicious, was that there was nothing to discuss. Free markets ruled, businesses spoke to businesses, and for the rest, all that mattered was brute force. The neocons liked this and it went with the old US military contempt for "Foggy Bottom". Since 2007 and the roles of Ryan Crocker, Emma Sky, and the State Department PRTs in getting them out of their self-dug hole in Iraq, you don't hear that so often.
Diplomacy is the weird and paradoxical medium in which states swim. (This is a trope of the book - people and other creatures manoeuvre through language, spaceships in space and in another convenient dimension, and states through diplo-space.) At the very least, it's a continuing exercise in killing as few people as possible, like emergency medicine. Like lawyers, it's one of the things I learnt to stop hating in the Bush years.
The ambassadors in Embassytown are rather odd creatures, selected, raised, and trained to think precisely the same thing at the same time and express it with great discretion and irritating charm. Meanwhile, the embassy staff are really in charge behind the scenes. Who the hell can he be thinking of?